BACTERIAL DISEASE: TUBERCULOSIS (TB)

BY: SAI MANOGNA (MSIWM014)

Introduction : 

Mycobacterium tuberculosis, a tubercle bacillus, is the TB causative agent. It belongs to a closely related species, including M bovis, M africanum, and M microti, in the M tuberculosis complex. The most common site for TB development is in the lungs; 85 percent of patients with TB have lung complaints. Extrapulmonary TB can emerge as part of a primary, or late, generalized infection.

Types of Tuberculosis :

Tuberculosis is categorized into two types: active illness or latent infection. Lung disease is the most common type of active TB, but it can invade other organs, known as “miliary TB.”

TB – Active :

Active TB is a disease in which TB bacteria rapidly grow and invade the body’s various organs. Cough, phlegm, chest pain, fatigue, weight loss, fever, chills, and night sweating are common symptoms of active TB. Via airborne transmission of infectious particles coughed up into the air, a person with active pulmonary TB disease may spread TB to others. 

TB Miliary : 

Miliary TB is a rare type of active disease in the bloodstream when TB bacteria find their way. The bacteria rapidly spread across the body in tiny nodules in this form, affecting multiple organs at once. This form of TB can quickly become fatal. 

Latent Infection with TB : 

Many of those infected with TB may not experience overt illness. They have no symptoms, and that could be common for their chest x-ray. Reaction to the interferon-gamma release assay (IGRA) or tuberculin skin test (TST) may be the sole manifestation of this encounter. There is an ongoing possibility, however, that the latent infection can escalate to active illness. Other diseases, such as HIV or drugs that weaken the immune system, increase the risk.

Incubation Period :

The time of incubation can vary from two to 12 weeks or so. An individual may remain infectious for a long time (provided that viable TB bacteria are present in the sputum) and may remain infectious for several weeks before they have undergone sufficient therapy.

Pathophysiology : 

1. M tuberculosis infection occurs most often from exposure to infected aerosols from the lungs or mucous membranes. 

2. Droplets are 1-5 μm in diameter in these aerosols; a single cough will produce 3000 infectious droplets in a person with active pulmonary TB, with as few as 10 bacilli required to initiate infection. Droplet nuclei are deposited within the terminal airspace of the lung when inhaled. 

3. The organism will grow for 2-12 weeks until they reach several 1000-10,000, enough to evoke a cellular immune response, detected by a tuberculin skin test reaction. 

4. Mycobacteria are strongly antigenic and encourage a nonspecific immune response that is robust. 

5. Their antigenicity is due to the activation of Langerhans cells, lymphocytes, and polymorphonuclear leukocytes by multiple cell wall constituents, including phospholipids, glycoproteins, and wax D. 

Individuals infected with M tuberculosis may take 1 of several infection routes, most of which do not lead to actual TB. The host immune system can clear or suppress infection in an inactive type called latent tuberculosis infection (LTBI), with resistant hosts regulating mycobacterial production at distant locations before active disease output. Patients with LTBI cannot spread TB.

As earlier mentioned, the most popular site for TB production is in the lungs; 85 percent of TB patients have pulmonary complaints. As part of primary infection, or late, generalized infection, extrapulmonary TB may occur. The most prominent sites of extrapulmonary disease are: common location of tuberculous lymphadenitis is in the neck and the sternocleidomastoid muscle; it is typically unilateral and causes little to no pain; advanced tuberculous lymphadenitis cases may suppurate and shape a sinus drain. As in the kidneys, bones, meninges, skin, choroids, and the lungs’ apices, contaminated end organs usually have high regional oxygen stress. The fundamental cause of M tuberculosis infection tissue destruction is linked to the organism’s ability to incite extreme host immune reactions to the antigenic cell wall proteins. 

Lesions with TB :

An epithelioid granuloma with central caseation necrosis is the usual lesion of TB. The common site of the primary lesion in the lung’s subpleural regions is within alveolar macrophages. Locally, Bacilli proliferate and spread to a Hillary node via the lymphatics, forming the Ghon complex. 

The early tubers are spherical, 0.5- to 3-mm nodules with 3 or 4 cell areas, displaying the following characteristics: 

a. A necrosis of the central caseate 

b. Lymphocyte-admixed inner cell region of epithelioid macrophages and Langhans giant cells 

c. An outer cell region with plasma cells, lymphocytes, and immature macrophages 

d. A fibrosis rim (in lesions that heal) 

Initial Lesions: Until symptomatic illness occurs, initial lesions may heal, and the infection becomes latent. Smaller tubercles can be fully resolved. Fibrosis happens when hydrolytic enzymes destroy tubercles, and a fibrous capsule surrounds larger lesions. Typically, these nodules contain viable mycobacteria and can be reactivated. Some nodules calcify or ossify and are readily seen on radiographs of the chest. 

Proliferative Lesions: Where the bacillary load is small and host cellular immune responses dominate proliferative lesions form. These tubers are compact, mixed with activated macrophages, and surrounded by proliferating fibrosis lymphocytes, plasma cells, and an outer rim. Mycobacteria intracellular killing is successful, and the bacillary load remains low. 

Exudative Lesions: Exudative lesions predominate when large numbers of bacilli and there are low host defenses. Such loose aggregates of immature macrophages, neutrophils, necrosis of fibrin, and caseation are mycobacterial growth sites. These lesions progress without treatment, and the infection spreads. 

Etiology : 

M tuberculosis, a slow-growing obligate aerobic and a facultative intracellular parasite, are responsible for TB. In parallel groups called cords, the organism grows. After decoloration with acid-alcohol, based on the acid-fast stains used for pathological detection, it retains several stains. 

Fig: Acid-fast bacillus smear. 

In Mycobacterium tuberculosis, acid-fast bacillus smear shows aerobic, non-spore-forming, nonmotile, facultative, curved intracellular rods measuring 0.2-0.5 μm by 2-4 μm are mycobacteria, including M tuberculosis. Mycolic, acid-rich, long-chain glycolipids and phospho lipoglycans (mycocides) are contained in their cell walls that protect mycobacteria from cell lysosomal attack retains red basic fuchsin dye (acid-fast stain) after acid rinsing. 

Transmission :

The only known source of M tuberculosis has been humans. The organism is transmitted from a person in the infectious stage of TB, primarily airborne aerosol (although transdermal and GI transmission have been reported). 

1. Exposure to M tuberculosis in immunocompetent individuals results in latent/dormant infection 

2. Modifications in host immune systems resulting in a decreasing immune effectiveness may enable M tuberculosis species to reactivate, tuberculosis stemming from a combination of the direct effects of infectious organism replications, and subsequent host immune responses to tuberculosis antigens.

3. By restriction fragment-length polymorphism study, molecular typing of M tuberculosis isolates in the United States indicates that more than one-third of new patient TB occurrences result from person-to-person transmission. The remainder comes from latent infection reactivation. 

Symptoms and signs :

Symptoms associated with active pulmonary TB (older people with TB do not have the usual signs and symptoms) are as follows: 

i. Coughing ii. anorexia and fever 

iii. Sweats at Night 

iv. hemoptysis 

v. Chest pain (may also be caused by acute tuberculous pericarditis) 

vi. Tiredness 

The following may be signs of tuberculous meningitis: 

i. Headache, which for 2-3 weeks has been either sporadic or chronic 

ii. Fever that is low-grade or absent 

iii. Subtle changes in mental state that may progress towards coma over days to weeks 

The following may be signs of skeletal TB :

i. Pain in the back or stiffness

ii. Tuberculous arthritis, usually affecting just 1 joint (the hip or knee most frequently, followed by the foot, elbow, wrist, and shoulder) 

Genitourinary TB symptoms can include the following: 

Pain Flanking, DYSURIA, frequent urination, symptoms that resemble pelvic inflammatory illness in women, a painful mass of the scrotum, prostatitis, orchitis, or epididymitis in men 

Gastrointestinal TB signs apply to the contaminated site and can include the following: 

i. Non Healing mouth ulcers or anus ulcers 

ii. Malabsorption (with a small intestine infection) 

iii. Swallowing problems (with the esophageal disease) 

iv. TB-related physical examination results depend on the organs involved.

v. Mimicking peptic ulcer disease (with gastric or duodenal infection) with stomach pain 

vi. Pain, diarrhea, or hematochezia (containing colon infection) 

The following may be present in patients with pulmonary TB: 

i. Abnormal sounds of breath, especially over the upper lobes or areas involved, 

ii. Rales or signs of bronchial breath, suggesting consolidation of the lungs 

Depending on the tissues involved, symptoms of extrapulmonary TB vary and can include the following: Perplexity, chorioretinitis, coma, cutaneous Injuries, neurological deficit, lymphadenopathy pathology. 

Active TB is not excluded by the lack of any relevant physical findings. In high-risk patients, especially those who are immunocompromised or elderly, classic symptoms are often absent. 

Causes : 

M. Bacteria that cause tuberculosis to induce TB. When a person with pulmonary TB coughs, sneezes, spits, laughs or speaks, they will propagate in droplets through the air. The infection can be transmitted only by individuals with active TB. However, most people with the disease can no longer spread the bacteria after receiving sufficient care for at least two weeks. 

Factors of Risk : 

When deciding whether a TB infection is likely to be transmitted, the following factors help: 

i. Total of expelled species 

ii. Immune condition of the person exposed 

iii. Duration of time of exposure to polluted air 

iv. Organisms’ concentration 

A specific risk to non-infected individuals is posed by infected persons living in crowded or closed environments. Approximately 20% (positive tuberculin skin test) of household contacts develop an infection. Micro Epidemics have occurred on transcontinental flights and in closed settings such as submarines. Hospital workers, inner-city residents, nursing home residents, and inmates often include groups at high risk for contracting the infection. 

The factors increasing the risk of acquiring active tuberculosis in an individual are : 

i. Infection with HIV 

ii. Diabetes mellitus (3fold increase in risk) 

iii. Immunosuppressive counseling

iv. Abuse of intravenous ( IV) medications 

v. Renal End-stage Disorder 

vi. With alcoholism 

vii. Malignancies of hematologic origin

viii. Silicosis 

ix. Less than five years of age

x. Antagonists of tumor necrosis factor-alpha (TNF-alp) 

xi. Head and neck cancer 

xii. Surgery for intestinal bypass or gastrectomy 

xiii. Chronic Syndromes of Malabsorption 

xiv. Low body weight-In comparison, obesity has been associated with a lower risk of active pulmonary TB in elderly patients

xv. Smoking-To minimizes the risk of relapse; smokers who develop TB should be advised to quit smoking. 

TB in Children : 

The potential for developing fatal miliary TB or meningeal TB is a primary concern in children younger than five years old. In children with TB, osteoporosis, sclerosis, and bone involvement are more common than adults with the condition. As a result of their high vascularity, the epiphyseal bones may be involved. Children also do not infect other children because they rarely develop a cough, and sputum development is scarce. Cases of child-child and child-adult transmission of TB are, however, well known. 

Genetic considerations : 

Tuberculosis genetics are very complex, involving several genes. Some of these genes provide essential elements of the immune system, while others include more complex mechanisms by which Mycobacterium species communicate with the human body. The genes that follow have polymorphisms that are connected with either tuberculosis susceptibility or safety. Also, regions such as 8q12-q13, the gene has not yet been identified, are associated with increased risk. 

Diagnosis : 

Methods of screening for TB include: 

Mantoux tuberculin skin test for active or latent infection (primary method) with purified protein derivative (PPD) 

An interferon-gamma release assay (IGRA) in vitro blood test with antigens unique to Mycobacterium tuberculosis for latent infection 

Obtain the following laboratory examinations for suspected TB patients: 

Acid-fast bacilli (AFB) smear and sputum culture obtained from the patient: no positive smear result does not preclude active TB infection; the most specific test for TB culture is the AFB culture. 

Serology of HIV in all TB patients and uncertain HIV status: HIV-infected individuals are at increased risk of TB 

Other diagnostic tests, including the following, can justify consideration: 

Immunospot Specific Enzyme-Linked (ELISpot) 

Tests for Nucleic acid amplification 

Community of blood 

Drug susceptibility testing should be followed in supportive cultures; symptoms and radiographic results do not distinguish multidrug-resistant TB (MDR-TB) from completely susceptible TB. 

Such testing can include the following: 

a. Study of Direct DNA Sequencing 

b. Molecular Automated Testing 

c. Drug resistance (MODS) and thin-layer agar (TLA) assays for microscopic observation 

d. Additional quick tests (e.g., BACTEC-460, luciferase reporter assays, ligase chain reaction, FASTPlaque TB-RIF) 

e. To test for potential related pulmonary findings, obtain a chest radiograph. 

Treatment : 

TB is cured with early detection and effective antibiotics. 

The correct type of antibiotic and the period of therapy will depend on: 

i. The overall health and age of the individual 

ii. If they have active or latent TB 

iii. The position of the infection 

iv. If the TB strain is immune to drugs 

v. Latent TB treatment can vary. It may mean taking an antibiotic for 12 weeks once a week or for nine months every day. 

Treatment for active TB can require 6-9 months of taking several drugs. The treatment would be more difficult if a person has a drug-resistant strain of TB. Completing the full course of treatment is significant, even if the symptoms go away. Some bacteria can survive and become immune to antibiotics if a person stops taking their medication early. The person may continue to develop drug-resistant TB in this case. 

Prevention: Ways of preventing anyone from being infected with TB include: 

i. Having an early diagnosis and treatment 

ii. Staying away from other individuals until the risk of infection is no longer present 

iii. Wearing a mask, shielding the mouth and rooms with ventilation 

iv. Vaccinating against TB 

In individual nations, as part of a routine immunization program, children receive an anti-TB injection, the bacillus Calmette-Guérin ( BCG) vaccine. 

The live strain of Mycobacterium bovis developed by Calmette and Guérin for use as an attenuated vaccine to prevent tuberculosis ( TB) and other mycobacterial infections is Bacille Calmette-Guérin (BCG). The vaccine was first given to humans in 1921 and remained the only vaccine for general use against TB. 

The BCG vaccine is the world’s most commonly administered vaccine; it has been given to over three billion people, mainly in the form of compulsory newborn immunization (as dictated by World Health Organization guidelines)[1]. Several BCG vaccines are used worldwide, manufactured by various manufacturers, and administered under different schedules. The BCG vaccine is also effective against other diseases, including leprosy and Buruli ulcer, for safety. Moreover, it is used in the treatment of superficial bladder carcinoma as an immunostimulant.

BACTERIAL DISEASE : LEPROSY

BY: SAI MANOGNA (MSIWM014)

Introduction : 

A chronic infection caused by the acid-fast, rod-shaped Mycobacterium leprae bacillus is leprosy. Leprosy is also known as Hansen’s disease. Two related diseases that mainly affect superficial tissues, especially the skin and peripheral nerves, maybe leprosy. A mycobacterial infection initially triggers a broad array of cellular immune responses. The second component of the condition, peripheral neuropathy with possible long-term effects, is then elicited by these immunologic events.

As a highly infectious and debilitating disease, leprosy was once feared, but nowadays, it does not spread quickly, and treatment is very successful. However, nerve damage can result in hands and feet being crippled, paralysis, and blindness if left untreated.

Classification of Leprosy :

The number and sort of skin sores have determined leprosy. The type of leprosy depends on specific symptoms and treatment. The forms are: 

Tuberculoid:  A moderate type of leprosy, which is less severe. People with this type only have one or a few patches (paucibacillary leprosy) of flat, pale-colored skin. Owing to nerve damage underneath, the affected region of the skin can feel numb. It is less infectious to tuberculoid leprosy than other types. 

Lepromatous:  Come on. A more extreme form of the disorder. It brings widespread skin bumps and rashes, numbness, and muscle weakness (multibacillary leprosy). It can also impact the nose, kidneys, and male reproductive organs. It is more infectious than leprosy caused by tuberculosis. 

Borderline: The tuberculoid and lepromatous symptoms are present for people with borderline leprosy. 

You can hear physicians use this simplified classification as well: 

Paucibacillary – single lesion (SLPB): One lesion 

Paucibacillary (PB): lesions from two to five 

Multibacillary (MB): Six lesions or more

Incubation period :

The incubation period is called the interval between contact with the bacteria and the appearance of symptoms. Symptoms typically take about 3 to 5 years to appear after coming into contact with the leprosy-causing bacteria. Up to 20 years later, some individuals do not show symptoms. The long incubation period of leprosy makes it very hard for doctors to determine when and where a person with leprosy has been infected.

Pathophysiology :

Depending on the host’s reaction to the organism, leprosy can manifest in various ways. 

1. The tuberculoid type of the disease that usually affects the skin and peripheral nerves are present in individuals who have a robust cellular immune response to M leprae. 

2. They tend to be dry and hypoesthetic, and the number of skin lesions is small. 

3. Typically, nerve activity is asymmetric. Owing to the low number of bacteria in the skin lesions, i.e., < 5 skin lesions, with no organisms on the smear, this type of the disease is often referred to as paucibacillary leprosy. 

4. In these people, the findings of skin tests with antigens from killed species are positive.

5. The lepromatous type of the disease, characterized by extensive skin involvement, is for individuals with limited cellular immune response. 

6. Infiltrated nodules and plaques are often identified as skin lesions, and nerve involvement appears to be symmetric in distribution. 

7. The organism grows best at 27-30 ° C; therefore, skin lesions tend to develop in the body’s colder areas, with sparing of the groin, axilla, and scalp. 

8. Owing to no small number of bacteria present in the lesions, i.e.,> 6 lesions, with potential bacilli visualization on the smear, this type of disease is often referred to as multibacillary leprosy. 

9. Skin test results for antigens from killed species are non-reactive.

Patients can also have symptoms of both types (indeterminate or borderline leprosy) but typically evolve to one or the other over time. Interestingly, most people exposed to leprosy never contract the disease, possibly because more than 95 percent of individuals are naturally immune to this disease.

Epidemiology :

In 2018, 208,619 new leprosy cases were reported globally, according to WHO estimates based on data from 159 countries. The worldwide prevalence was 184,212 cases (rate, 0.2/10,000) reported at the end of 2018. In 2018, 79.6 percent of all new leprosy cases were in Brazil, Indonesia, and India. Furthermore, in 2018, 23 priority countries accounted for 96 percent of cases globally.

a. Mortality/Morbidity :

Leprosy is never lethal. The nerve damage and crippling sequelae are the main consequences of infection. 33-56 percent of newly diagnosed patients have already demonstrated symptoms of compromised nerve function[11], according to one report. According to reports, three million individuals who have undergone multidrug treatment for leprosy have suffered impairment due to nerve damage. While the skin and peripheral nerves are involved in both lepromatous leprosy and tuberculoid leprosy, tuberculoid leprosy has more severe manifestations. Nerve involvement contributes to sensory and motor loss of control, leading to repeated trauma and amputation. Most generally, the ulnar nerve is involved. 

Damage to the following nerves is related to characteristic leprosy impairment: 

i. Ulnar and Median-Hand Clawed 

ii. Tibial posterior-Plantar insensitivity and clawed toes 

iii. Peroneal Common-Foot Drop 

iv. Radial nerves of the cutaneous, nasal, and greater auricular

b. Race : 

Leprosy was once globally endemic, although no predilection for the race is recognized. The incidence of leprosy fell significantly in northern Europe and North America in the late 1800s, and the disease is now recorded mainly in tropical areas. 

c. Gender :

In males, leprosy is typically more common than in females, with a 2:1 male-to-female ratio. The prevalence of leprosy among females is equal to or greater than that of males in some areas of Africa. 

d. Age :

Leprosy can occur at any age, but the age-specific occurrence of leprosy in developed countries peaks in children younger than ten years, accounting for 20 percent of leprosy cases. In infants, leprosy is very rare; however, they are at relatively high risk of maternal leprosy, particularly in cases of lepromatous leprosy or mid borderline leprosy.

e. HIV Coinfection :

Preliminary data suggest that, unlike tuberculosis, HIV coinfection does not appear to affect leprosy. Besides, coinfection with HIV does not seem to affect the lepromatous to tuberculoid leprosy ratio.

Symptoms of Leprosy 

Leprosy mostly affects the skin and nerves, called the peripheral nerves, beyond the brain and spinal cord. 

Disfiguring skin sores, bumps, or lumps that do not go down for several weeks or months is leprosy’s principal symptom. The sores on the skin are pale-colored. Nerve damage leads to loss of sensation in legs and arms, weakness of muscles.

Causes :

Exactly how leprosy is transmitted is not clear. When an individual coughs or sneezes with leprosy, they can spread droplets containing M. The leprosy bacteria that someone else breathes in. For leprosy to be transmitted, near physical contact with an infected individual is required. Shaking hands, kissing, or sitting beside them during a meal on a bus or at a table, do not transmit the disease.

Pregnant leprosy mothers are unable to pass it on to their newborn babies. Neither is it spread through sexual touch.

Risk Factors :

Leprosy can permanently damage skin, nerves, arms, legs, feet, and eyes without care. 

Leprosy complications may include: 

Glaucoma or blindness 

Iritis 

Loss of hair 

For infertility 

Facial disfigurement (including permanent swelling, bumps, and lumps) 

Erectile dysfunction in males and infertility 

Failure of the kidney 

Weakness in the muscles contributing to claw-like hands or not being able to stretch feet 

The inside of the nose is permanently damaged, which can lead to nosebleeds and a chronic stuffy nose 

Permanent nerve damage, including those in the arms, legs, and feet, outside the brain and spinal cord 

Damage to the nerves can lead to a dangerous loss of feeling. Do not experience pain when one gets cuts, burns, or other injuries to hands, legs, or feet if they have leprosy-related nerve damage.

Diagnosis :

It is possible to distinguish Hansen’s disease by the presence of skin patches that may look lighter or darker than normal skin. The skin areas affected can often be reddish. The lack of sensation is prominent in these skin patches. For a needle, one cannot feel a light brush or a prick. 

The physician will take a sample of skin or nerve (through skin or nerve biopsy) and check for bacteria under the microscope and confirm your diagnosis, and may even conduct tests to rule out any skin diseases.

Treatment :

It is possible to treat leprosy. 16 million people with leprosy have been healed in the last 2 decades. The World Health Organization provides free care for all people with leprosy. 

Therapy relies on the type of leprosy they have. For treatment, antibiotics are used. Doctors recommend treatment on a long-term basis, usually for 6 months to a year. You may need to take antibiotics longer if you are suffering from severe leprosy. The nerve damage that comes with leprosy cannot be treated with antibiotics. 

A standard treatment for leprosy that combines antibiotics is multidrug therapy (MDT). That means you are going to take two or more drugs, mostly antibiotics: 

Paucibacillary leprosy: Two antibiotics, such as dapsone, are used every day, and rifampicin is used once a month. 

Multibacillary leprosy: In addition to daily dapsone and monthly rifampicin, you can take a daily dose of the antibiotic clofazimine. For 1-2 years, you will undergo multidrug treatment, and then you will be healed.

Antibiotics: The bacteria causing leprosy can be destroyed by antibiotics used during treatment. However, though medication may cure the condition and keep it from getting worse, nerve damage or physical disfigurement may have existed before a diagnosis is not reversed. Thus, before any irreversible nerve damage occurs, the condition must be detected as soon as possible.

Transmission : 

The exact way Hansen’s disease spreads between people is not understood. Scientists claim that it can happen if a person with Hansen’s disease coughs or sneezes, and a healthy person breathes in the droplets that contain the bacteria. Prolonged close contact is required with someone with untreated leprosy for several months. 

You do not get leprosy from casual contact with a person who has Hansen’s disease, such as: shaking or hugging palms, sitting for a meal together, sitting on the bus next to each other. 

During pregnancy, Hansen’s disease is also not transmitted from a mother to her unborn baby, and it does not spread by sexual contact. It is often challenging to locate the infection source due to the bacteria’s slow-growing nature and the long time to cause symptoms of the disease.

For general health purposes, if possible, avoid contact with armadillos. Speak to your physician if you have come into touch with an armadillo and are anxious about having Hansen’s disease. Over time, the doctor will follow up with you and conduct annual skin tests to see if the disease progresses. 

Prevention : 

In high-risk areas, awareness campaigns on leprosy are essential to enable patients and their families, who have been traditionally shunned from their communities, to come forward and receive care. 

Early diagnosis and multidrug therapy treatment is the most effective way to avoid leprosy disabilities and avoid further disease spread. However, the Bacille Calmette-Guérin ( BCG) vaccine is partially protective against leprosy.

BACTERIAL DISEASE – TYPHOID

BY: SAI MANOGNA (MSIWM012)

Introduction :

Any disease caused by bacteria involves bacterial diseases. Bacteria, which are small types of life that can only be seen through a microscope, are microorganisms. Viruses, some fungi, and some parasites include other types of microorganisms. Millions of bacteria usually reside in the skin, intestines, and genitals. The vast majority of bacteria cause no disease, and many bacteria are beneficial and even required for good health. Often, these bacteria are referred to as good bacteria or healthy bacteria. 

Pathogenic bacteria are considered dangerous bacteria that cause bacterial infections and illnesses. When these invade the body and begin to replicate and crowd out healthy bacteria or develop in typically sterile tissues, bacterial diseases occur. Toxins that damage harmful bacteria can also release the body.

Typhoid :

An infectious, potentially life-threatening bacterial infection is typhoid fever, also called enteric fever. Typhoid fever is caused by the Salmonella enteric serotype Typhi bacterium (also known as Salmonella Typhi), carried into the blood and digestive tract by infected humans and spreads by food drinking water contaminated with infected feces to others. Typhoid fever signs include fever, rash, and pain in the abdomen. 

Fortunately, typhoid fever, particularly in its early stages, is treatable, and if one chooses to live in or fly to high-risk areas of the world, a vaccine is available to help prevent the disease.

Incubation Period :

Typhoid and paratyphoid infections have an incubation period of 6-30 days. With steadily rising exhaustion and a fever that rises daily from low-grade to as high as 102 ° F to 104 ° F ( 38 ° C to 40 ° C) by the third to the fourth day of illness, the onset of illness is insidious. In the morning, fever is usually the lowest, peaking in the late afternoon or evening. 

Pathophysiology :

1. When present in the gut, all pathogenic Salmonella species are swallowed up by phagocytic cells, moving them through the mucosa and presenting them to the lamina propria macrophages. 

2. Across the distal ileum and colon, nontyphoidal salmonellae are phagocytized. Macrophages identify pathogen-associated molecular patterns (PAMPs) such as flagella and lipopolysaccharides with the toll-like receptor (TLR)-5 and TLR-4 / MD2 / CD-14 complex. 

3. Macrophages and intestinal epithelial cells are then attracts the interleukin 8 (IL-8) T cells and neutrophils, inducing inflammation and suppressing the infection. 

4. Unlike the nontyphoidal salmonellae, S typhi and paratyphi penetrate mainly via the distal ileum into the host system. They have specialized fimbriae that bind to the epithelium over lymphoid tissue clusters in the ileum, the critical point of relay for macrophages moving into the lymphatic system from the stomach. 

5. The bacteria then attract more macrophages by activating their host macrophages.

6. Typhoidal salmonella co-opts the cellular machinery of the macrophages for their reproduction, as they are transported to the thoracic duct and lymphatics to the mesenteric lymph nodes and then to the reticuloendothelial tissues of the spleen, bone marrow, liver, and lymph nodes. 

7. Once there, until some critical density is reached, they pause and begin to multiply. Afterward, to reach the rest of the body, the bacteria cause macrophage apoptosis, breaking out into the bloodstream. 

8. By either bacteria or direct extension of infected bile, the bacteria then invade the gallbladder. The effect is that in the bile, the organism re-enters the gastrointestinal tract and reinfects patches of Peyer. 

9. Usually, bacteria that do not reinfect the host are shed in the stool and are then available for other hosts to invade.

Epidemiology :

The International 

Worldwide, typhoid fever occurs mostly in developing countries where sanitary conditions are low. In Asia, Latin America, Africa, the Caribbean, and Oceania, typhoid fever is endemic, but 80 percent of cases originate from Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, or Vietnam. In underdeveloped countries, typhoid fever is the most common. About 21.6 million people are infected by typhoid fever (incidence of 3.6 per 1,000 population), and an estimated 200,000 people are killed every year. 

Most cases of typhoid fever occur among foreign travelers in the United States. The average annual incidence of typhoid fever by county or area of departure per million travelers from 1999-2006 was as follows:

Outside Canada / United States, Western Hemisphere-1.3 

Africa-7.6 Africa 

Asia-10.5. 

India-89 (in 2006 122) 

Complete (except for Canada / United States, for all countries)-2.2 

Morbidity / Mortality :

Typically, typhoid fever is a short-term febrile condition with timely and effective antibiotic care, requiring a median of 6 days of hospitalization. It has long-term sequelae and a 0.2 percent mortality risk when treated. Untreated typhoid fever is a life-threatening disease that lasts many weeks, frequently affecting the central nervous system, with long-term morbidity. In the pre-antibiotic age, the case fatality rate in the United States was 9 -13%.

Sex : 

Fifty-four percent of cases of typhoid fever recorded between 1999 and 2006 in the United States included males. Moreover, race has no predilection. 

Age : 

Many confirmed cases of typhoid fever include children of school age and young adults. The true incidence is, however, thought to be higher among very young children and babies. The presentations may be atypical, that ranges from a mild febrile disease to severe convulsions, and the infection of S.typhi may go unrecognized. In the literature, this could account for contradictory reports that this category has very high or very low morbidity and mortality rate.

Symptoms :

Typhoid fever symptoms typically occur five to 21 days after food or water infected with Salmonella Typhi bacteria is consumed and can last up to a month or longer. Typical Typhoid Fever signs include: 

i. Pressure in the abdomen and tenderness 

ii. Perplexity 

iii. Fatigue and Weakness 

iv. Trouble focusing 

v. Constipation or diarrhea

vi. Headaches 

vii. The Nosebleeds 

viii. A dry cough 

ix. Impoverished appetite 

x. Rash (small, flat, red rashes that are also known as rose spots on the belly and chest) 

xi. Lethargy 

xii. Swollen lymph ganglions 

xiii. Chills and Fever. With typhoid fever, persistent fever of 104 degrees Fahrenheit is not rare. 

Symptoms: life-threatening 

Typhoid fever, including intestinal bleeding, kidney failure, and peritonitis, may lead to life-threatening complications. If they are with anyone who has any of these signs, seek urgent medical attention : 

Bloody stools or severe rectal bleeding 

A shift in consciousness or alertness level 

Confusion, delirium, disorientation, or hallucinations 

Unexplained or chronic dizziness 

Dry, broken lips, tongue, or mouth 

Unresponsiveness or lethargy 

Not urinating tiny quantities of tea-colored urine or urinating it. 

Extreme pain in the abdomen 

Extreme diarrhea in patients 

Extreme signs in infants include sunken fontanel (soft spot) at the top of the head, lethargy, no weeping tears, little or no wet diapers, and diarrhea. Infants two months of age or younger, be especially concerned about fever.

Causes :

The Salmonella Enteric Serotype Typhi (Salmonella Typhi) bacterium is responsible for typhoid fever. Via ingestion of infected food and water, Salmonella Typhi can enter and infect the body. By being washed in polluted water or being touched by an infected person with unwashed hands, food can become contaminated with the bacteria. Drinking water can become infected with untreated Salmonella Typhi-containing sewage.

Risk factors :

A variety of variables improves the chances of contracting typhoid fever. In developing, non-industrialized countries, typhoid fever is a significant health threat, although rare in the United States, Canada, and other industrialized countries. Factors of vulnerability include: 

i. Near contact with individuals infected or recently infected 

ii. Travel to areas with more frequent and widespread outbreaks of typhoid fever, such as India, Southeast Asia, Africa, and South America

iii. Avoiding contact with a person who has or has signs of typhoid fever, such as abdominal pain, headache, and fever

iv. Residence in a developing world or continent with inadequate treatment facilities for water and sewage or poor hygiene practices 

v. Due to diseases such as HIV / AIDS or drugs such as corticosteroids, the compromised immune system 

vi. Do not eat fruits and vegetables that are unable to peel. Eating fully cooked, hot, and still steaming foods. Unless it is made from distilled water, drinking only bottled water and not using ice 

vii. Before visiting high-risk areas, having vaccinated against typhoid fever 

viii. During and after contact with an individual who has typhoid fever or with an individual who has signs of typhoid fever, such as abdominal pain, headache, rash, and fever, washing hands regularly with soap and water for 15 seconds 

ix. Washing hands regularly for at least 15 seconds with soap and water, particularly before handling food and after using the toilet, touching feces, and changing diapers

Diagnosis :

1. Salmonella bacteria infiltrate the small intestine following the ingestion of infected food or drink and temporarily enter the bloodstream. 

2. The bacteria are transported into the liver, spleen, and bone marrow by white blood cells, replicating and re-enter the bloodstream. 

3. At this point, people develop symptoms, including fever. Bacteria invade the biliary system, gallbladder, and the intestinal lymphatic tissue. 

4. Here, in high numbers, they multiply. In the digestive tract, the bacteria move and can be found in stool samples. 

5. Blood or urine samples will be used to diagnose if a test result is not exact.

Treatment :

Typhoid fever is a treatable condition, and a complete course of antibiotics, such as ampicillin, trimethoprim-sulfamethoxazole, or ciprofloxacin, may also be used to cure it. Treatment can include rehydration with intravenous fluids and electrolyte replacement therapy in some severe cases. Usually, with care, symptoms improve within two to four weeks. If they have not been treated completely, symptoms may return. One needs to take the antibiotics for as long as needed to treat typhoid fever and follow up with the doctor for a series of blood and stool tests to ensure that they are no longer infectious. 

Few people infected with Salmonella Typhi become carriers, which indicates that the bacteria are present in the intestines and bloodstream and are shed in the stool even after they no longer have disease symptoms. Because of the carrier effect, it is essential to understand that they might still transmit the disease by contaminating food and water even after receiving treatment for typhoid fever. Before traveling outside developed regions, such as the United States, Canada, northern Europe, Australia, New Zealand, and Japan, it is vital to avoid the disease by getting vaccinated. During epidemic outbreaks, immunizations are also recommended, although the vaccination is not successful.

Prevention :

A larger number of typhoid cases usually occur in countries with less access to clean water and washing facilities. 

Immunization :

Vaccination is advised while traveling to a region where typhoids are prevalent. 

It is recommended to get vaccinated against typhoid fever before traveling to a high-risk area. 

Oral treatment or a one-off injection can be done : 

Oral: an attenuated, live vaccine. It consists of 4 tablets, one of which is taken every other day, the last of which is taken one week before departure. 

Shoot, the inactivated vaccine, was given two weeks before the ride. 

Vaccines are not 100 percent successful, and when eating and drinking, caution should always be exercised. 

Two forms of typhoid vaccine are available, but a more potent vaccine is still required. The vaccine’s live, oral form is the strongest of the two. It also protects individuals from infection 73 percent of the time after three years. This vaccine has more side effects, however. If the person is currently ill or if he or she is under the age of 6 years, vaccination should not begin. The live oral dose should not be taken by someone who has HIV. There may be adverse effects of a vaccine. One in every 100 people is going to feel a fever. There may be stomach complications following the oral vaccine, nausea, and headache. For any vaccine, however, serious side effects are uncommon. 

Typhoid removal :

Even if typhoid symptoms have passed, it is still possible to bear the bacteria, making it impossible to stamp out the disease because when washing food or communicating with others, carriers whose symptoms have terminated may be less vigilant. 

Prevention of Infection :

Via touch and ingestion of contaminated human waste, typhoid is propagated. This can happen through a source of water that is tainted or when food is treated. 

Some general rules to obey while traveling to help reduce the risk of typhoid infection are the following: 

i. Drink water, preferably carbonated, in glasses. 

ii. Do not have ice for drinks. Stop raw fruit and vegetables, cut the fruit, and not eat the cut on your own. Eat only food that is still hot, and avoid eating at street food stands.

iii. If it is impossible to acquire bottled water, ensure the water is heated for at least one minute on a rolling boil before consumption. 

iv. Be wary of eating something that anyone else has dealt with. 

Related Disorders :

There may be similar symptoms of the following conditions to those of typhoid fever. For a differential diagnosis, similarities may be helpful: 

Salmonella Poisoning :

In foodborne diseases, this is the most common cause of disease. These bacteria can contaminate meat, dairy, and vegetable products. In warm weather and children under the age of seven, outbreaks are more prevalent. The most common initial symptoms are nausea, vomiting, and chills. These are accompanied by stomach pain, diarrhea, and fever that can last for several weeks to five days. Intoxication with salmonella is a type of gastroenteritis. The CDC reports about 2 to 4 million salmonellosis cases per year in the United States. 

Cholera :

Cholera is a bacterial infection characterized by extreme diarrhea and vomiting that affects the whole small intestine. A toxin produced by the bacteria Vibrio cholerae is the source of the symptoms. The disease is transmitted by drinking water or consuming fish, vegetables, and other foods contaminated with Cholera’s excrement.

Botulism :

Botulism is also a form of gastroenteritis caused by a bacterial toxin. A neuromuscular poison is this toxin. In three types, it occurs foodborne, wound, and infantile botulism. The foodborne type is the most popular. Besides nausea, vomiting, diarrhea, and stomach pain, the patient can feel exhaustion, fatigue, headache, and dizziness.

Ptomaine Poisoning in the United States’ fourth most prevalent cause of bacterial foodborne disease. It is caused by the enterotoxin protein released after consuming foods that are contaminated, usually meat products. Extreme stomach cramps and diarrhea are characteristics of the disease. Nausea also happens sometimes. Vomiting and fever are rare.