Paratuberculosis | |
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Other names | Johne's disease |
Pronunciation |
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Specialty | Veterinary medicine |
Paratuberculosis is a contagious, chronic and sometimes fatal infection that primarily affects the small intestine of ruminants. [1] It is caused by the bacterium Mycobacterium avium subspecies paratuberculosis. Infections normally affect ruminants (mammals that have four compartments of their stomachs, of which the rumen is one), but have also been seen in a variety of nonruminant species, including rabbits, foxes, and birds. Horses, dogs, and nonhuman primates have been infected experimentally. Paratuberculosis is found worldwide, with some states in Australia (where it is usually called bovine Johne's disease or BJD) being the only areas proven to be free of the disease. [2] At least in Canada, the signs of BJD usually start when cattle are four to seven years of age, and then usually only are diagnosed in one animal at a time. [3] Cattle "with signs of Johne’s disease shed billions of bacteria through their manure and serve as a major source of infection for future calves." [4]
Some sources define "paratuberculosis" by the lack of Mycobacterium tuberculosis , rather than the presence of any specific infectious agent, [5] leaving ambiguous the appropriateness of the term to describe Buruli ulcer or Lady Windermere syndrome.
The disease, discovered by Heinrich A. Johne, a German bacteriologist and veterinarian, in 1905, is caused by a bacterium named Mycobacterium avium subspecies paratuberculosis, an acid-fast bacillus, often abbreviated MAP. MAP is akin to, but distinct from, Mycobacterium tuberculosis , the main cause of tuberculosis in humans, and Mycobacterium bovis , the main cause of tuberculosis in cattle and occasionally also in humans. MAP is 99% genetically related to Mycobacterium avium , but has different phenotypic characteristics, such as:[ citation needed ]
Also, the environmental distribution of MAP is markedly different from that of M. avium, which can produce mycobactin, so can grow and multiply outside the body.[ citation needed ]
Pasteurization is used to kill the causal agent, M. paratuberculosis, by heating cow's milk for a short time and then immediately cooling it. [6] [ obsolete source ]
In cattle, the main signs of paratuberculosis are diarrhea and wasting. Most cases are seen in 2- to 6-year-old animals. The initial signs can be subtle, and may be limited to weight loss, decreased milk production, or roughening of the hair coat. The diarrhea is usually thick, without blood, mucus, or epithelial debris, and may be intermittent. Several weeks after the onset of diarrhea, a soft swelling may occur under the jaw. Known as "bottle jaw" or intermandibular edema, this symptom is due to protein loss from the bloodstream into the digestive tract. Paratuberculosis is progressive; affected animals become increasingly emaciated and usually die as the result of dehydration and severe cachexia.[ citation needed ]
Signs are rarely evident until two or more years after the initial infection, which usually occurs shortly after birth. Animals are most susceptible to the infection in the first year of life. Newborns most often become infected by swallowing small amounts of infected manure from the birthing environment or udder of the mother. In addition, newborns may become infected while in the uterus or by swallowing bacteria passed in milk and colostrum. Animals exposed at an older age, or exposed to a very small dose of bacteria at a young age, are not likely to develop clinical disease until they are much older than two years.[ citation needed ]
The clinical signs are similar in other ruminants. In sheep and goats, the wool or hair is often damaged and easily shed, and diarrhea is uncommon. In deer, paratuberculosis can progress rapidly. Intestinal disease has also been reported in rabbits and nonhuman primates.[ citation needed ]
Unlike cattle and sheep, infections in deer often present with clinical illness in animals under one year of age.[ citation needed ]
The primary site targeted by Johne's disease is the lower part of the intestine known as the ileum. The wall of the ileum contains a large number of pockets of lymphoid tissue known as Peyer's patches that lie just beneath the interior surface of the intestine. Peyer's patches are clusters of macrophages and lymphocytes organized much like lymph nodes. Covering Peyer's patches are a layer of cells called M cells. These cells function to sample the content of the lumen of the intestines and pass antigens (bacteria) through to the underlying cells of the Peyer's patch to "show" these antigens to the macrophages and lymphocytes. This is a means of "educating" the cells in a young animal about its environment, and is a protective mechanism designed to help the animal become immune to pathogens in its environment.[ citation needed ]
Unfortunately, when M cells bring M. paratuberculosis to the Peyer's patch, the bacteria find an ideal place for growth. Macrophages in Peyer's patches engulf M. paratuberculosis for the purpose of destroying the foreign invader, but for reasons yet unclear, these macrophages fail to do this. Inside a macrophage, M. paratuberculosis multiplies until it eventually kills the cell, spreads, and infects other nearby cells. In time, other parts of the ileum and other regions of the body are teeming with millions of the mycobacteria. How M. paratuberculosis neutralizes or evades the normally efficient bacterial killing mechanisms of the macrophages is unknown, although the unusually resistant cell wall of mycobacteria likely plays an important role.[ citation needed ]
The animal's immune system reacts to the M. paratuberculosis invasion by recruiting more macrophages and lymphocytes to the site of the infection. The lymphocytes release a variety of chemicals signals, called cytokines, in an attempt to increase the bacterial killing power of the macrophages. Macrophages fuse together, forming large cells, called multinucleated giant cells, in an apparent attempt to kill the mycobacteria. Infiltration of infected tissues with millions of lymphocytes and macrophages leads to visible thickening of the intestines. This prevents nutrient absorption, and diarrhea results. Late in the infection, antibody production by the animal occurs to M. paratuberculosis in serum of animals, and is an indicator that clinical signs of disease and death from the infection will soon follow.[ citation needed ]
For goats infected with this disease, the most apparent sign of having it is their bodies wasting away, even with a sufficient diet. If a goat develops Johne's and it has diarrhea, it is most likely going to die. When it has diarrhea, the goat is at the last stages of the disease. Herds should be tested once or twice a year to maintain the health and keep out the disease.[ citation needed ]
In an endemic herd, only a minority of the animals develops clinical signs; most animals either eliminate the infection or become asymptomatic carriers. The mortality rate is about 1%, but up to 50% of the animals in the herd can be asymptomatically infected, resulting in losses in production. Once the symptoms appear, paratuberculosis is progressive and affected animals eventually die. The percentage of asymptomatic carriers that develop overt disease is unknown. [7]
MAP is capable of causing Johne's-like symptoms in humans, though difficulty in testing for MAP infection presents a diagnostic hurdle. [8]
As of October 2019, neither the World Health Organization nor any individual nation had declared Johne's disease to be zoonotic. [1]
Clinical similarities are seen between Johne's disease in ruminants and inflammatory bowel disease in humans, [9] and because of this, some researchers contend the organism is causative factor in Crohn's disease. [10] [11] However, epidemiologic studies have provided variable results; in certain studies, the organism (or an immune response directed against it) has been much more frequently found in patients with Crohn's disease than asymptomatic people.[ citation needed ]
Paratuberculosis is a reportable disease in some states of the US. [12] US Federal regulations prohibit culture positive or DNA test-positive animals from being moved across state lines except for slaughter.[ citation needed ]
Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any segment of the gastrointestinal tract. Symptoms often include abdominal pain, diarrhea, fever, abdominal distension, and weight loss. Complications outside of the gastrointestinal tract may include anemia, skin rashes, arthritis, inflammation of the eye, and fatigue. The skin rashes may be due to infections as well as pyoderma gangrenosum or erythema nodosum. Bowel obstruction may occur as a complication of chronic inflammation, and those with the disease are at greater risk of colon cancer and small bowel cancer.
Mycobacterium tuberculosis, also known as Koch's bacillus, is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, M. tuberculosis has an unusual, waxy coating on its cell surface primarily due to the presence of mycolic acid. This coating makes the cells impervious to Gram staining, and as a result, M. tuberculosis can appear weakly Gram-positive. Acid-fast stains such as Ziehl–Neelsen, or fluorescent stains such as auramine are used instead to identify M. tuberculosis with a microscope. The physiology of M. tuberculosis is highly aerobic and requires high levels of oxygen. Primarily a pathogen of the mammalian respiratory system, it infects the lungs. The most frequently used diagnostic methods for tuberculosis are the tuberculin skin test, acid-fast stain, culture, and polymerase chain reaction.
Mycobacterium is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis and leprosy in humans. The Greek prefix myco- means 'fungus', alluding to this genus' mold-like colony surfaces. Since this genus has cell walls with a waxy lipid-rich outer layer that contains high concentrations of mycolic acid, acid-fast staining is used to emphasize their resistance to acids, compared to other cell types.
Whipple's disease is a rare systemic infectious disease caused by the bacterium Tropheryma whipplei. First described by George Hoyt Whipple in 1907 and commonly considered as a gastrointestinal disorder, Whipple's disease primarily causes malabsorption, but may affect any part of the human body, including the heart, brain, joints, skin, lungs and the eyes. Weight loss, diarrhea, joint pain, and arthritis are common presenting symptoms, but the presentation can be highly variable in certain individuals, and about 15% of patients do not have the standard signs and symptoms.
Campylobacteriosis is among the most common infections caused by a bacterium in humans, often as a foodborne illness. It is caused by the Campylobacter bacterium, most commonly C. jejuni. It produces an inflammatory, sometimes bloody, diarrhea or dysentery syndrome, and usually cramps, fever and pain.
Feline leukemia virus (FeLV) is a retrovirus that infects cats. FeLV can be transmitted from infected cats when the transfer of saliva or nasal secretions is involved. If not defeated by the animal's immune system, the virus weakens the cat's immune system, which can lead to diseases which can be lethal. Because FeLV is cat-to-cat contagious, FeLV+ cats should only live with other FeLV+ cats.
Mycobacterium avium subspecies paratuberculosis (MAP) is an obligate pathogenic bacterium in the genus Mycobacterium. It is often abbreviated M. paratuberculosis or M. avium ssp. paratuberculosis. It is the causative agent of Johne's disease, which affects ruminants such as cattle, and suspected causative agent in human Crohn's disease and rheumatoid arthritis. The type strain is ATCC 19698.
Salmonellosis is a symptomatic infection caused by bacteria of the Salmonella type. It is the most common disease to be known as food poisoning, these are defined as diseases, usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. In humans, the most common symptoms are diarrhea, fever, abdominal cramps, and vomiting. Symptoms typically occur between 12 hours and 36 hours after exposure, and last from two to seven days. Occasionally more significant disease can result in dehydration. The old, young, and others with a weakened immune system are more likely to develop severe disease. Specific types of Salmonella can result in typhoid fever or paratyphoid fever. Typhoid fever and paratyphoid fever are specific types of salmonellosis, known collectively as enteric fever, and are, respectively, caused by salmonella typhi & paratyphi bacteria, which are only found in humans. Most commonly, salmonellosis cases arise from salmonella bacteria from animals, and chicken is a major source for these infections.
Gut-associated lymphoid tissue (GALT) is a component of the mucosa-associated lymphoid tissue (MALT) which works in the immune system to protect the body from invasion in the gut.
Clofazimine, sold under the brand name Lamprene, is a medication used together with rifampicin and dapsone to treat leprosy. It is specifically used for multibacillary (MB) leprosy and erythema nodosum leprosum. Evidence is insufficient to support its use in other conditions though a retrospective study found it 95% effective in the treatment of Mycobacterium avium complex (MAC) when administered with a macrolide and ethambutol, as well as the drugs amikacin and clarithromycin. However, in the United States, clofazimine is considered an orphan drug, is unavailable in pharmacies, and its use in the treatment of MAC is overseen by the Food and Drug Administration. It is taken orally.
Mycobacterium avium-intracellulare infection (MAI) is an atypical mycobacterial infection, i.e. one with nontuberculous mycobacteria or NTM, caused by Mycobacterium avium complex (MAC), which is made of two Mycobacterium species, M. avium and M. intracellulare. This infection causes respiratory illness in birds, pigs, and humans, especially in immunocompromised people. In the later stages of AIDS, it can be very severe. It usually first presents as a persistent cough. It is typically treated with a series of three antibiotics for a period of at least six months.
Ovine rinderpest, also commonly known as peste des petits ruminants (PPR), is a contagious disease primarily affecting goats and sheep; however, camels and wild small ruminants can also be affected. PPR is currently present in North, Central, West and East Africa, the Middle East, and South Asia. It is caused by Morbillivirus caprinae in the genus Morbillivirus, and is closely related to, among others, Morbillivirus pecoris, Morbillivirus hominis, and Morbillivirus canis. The disease is highly contagious, and can have an 80–100% mortality rate in acute cases in an epizootic setting. The virus does not infect humans.
Anaplasmosis is a tick-borne disease affecting ruminants, dogs, and horses, and is caused by Anaplasma bacteria. Anaplasmosis is an infectious but not contagious disease. Anaplasmosis can be transmitted through mechanical and biological vector processes. Anaplasmosis can also be referred to as "yellow bag" or "yellow fever" because the infected animal can develop a jaundiced look. Other signs of infection include weight loss, diarrhea, paleness of the skin, aggressive behavior, and high fever.
Mycobacterium avium complex is a group of mycobacteria comprising Mycobacterium intracellulare and Mycobacterium avium that are commonly grouped because they infect humans together; this group, in turn, is part of the group of nontuberculous mycobacteria. These bacteria cause Mycobacterium avium-intracellulare infections or Mycobacterium avium complex infections in humans. These bacteria are common and are found in fresh and salt water, in household dust and in soil. MAC bacteria usually cause infection in those who are immunocompromised or those with severe lung disease.
The abdominopelvic cavity is a body cavity that consists of the abdominal cavity and the pelvic cavity. The upper portion is the abdominal cavity, and it contains the stomach, liver, pancreas, spleen, gallbladder, kidneys, small intestine, and most of the large intestine. The lower portion is the pelvic cavity, and it contains the urinary bladder, the rest of the large intestine, and the internal reproductive organs.
Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba Entamoeba histolytica. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic ulcerations, abdominal pain, diarrhea, or bloody diarrhea. Complications can include inflammation and ulceration of the colon with tissue death or perforation, which may result in peritonitis. Anemia may develop due to prolonged gastric bleeding.
Shigatoxigenic Escherichia coli (STEC) and verotoxigenic E. coli (VTEC) are strains of the bacterium Escherichia coli that produce Shiga toxin. Only a minority of the strains cause illness in humans. The ones that do are collectively known as enterohemorrhagic E. coli (EHEC) and are major causes of foodborne illness. When infecting the large intestine of humans, they often cause gastroenteritis, enterocolitis, and bloody diarrhea and sometimes cause a severe complication called hemolytic-uremic syndrome (HUS). Cattle are an important natural reservoir for EHEC because the colonised adult ruminants are asymptomatic. This is because they lack vascular expression of the target receptor for Shiga toxins. The group and its subgroups are known by various names. They are distinguished from other strains of intestinal pathogenic E. coli including enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), and diffusely adherent E. coli (DAEC).
Escherichia coli is a gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most E. coli strains are harmless, but pathogenic varieties cause serious food poisoning, septic shock, meningitis, or urinary tract infections in humans. Unlike normal flora E. coli, the pathogenic varieties produce toxins and other virulence factors that enable them to reside in parts of the body normally not inhabited by E. coli, and to damage host cells. These pathogenic traits are encoded by virulence genes carried only by the pathogens.
The co-epidemic of tuberculosis (TB) and human immunodeficiency virus (HIV) is one of the major global health challenges in the present time. The World Health Organization (WHO) reports 9.2 million new cases of TB in 2006 of whom 7.7% were HIV-infected. Tuberculosis is the most common contagious infection in HIV-Immunocompromised patients leading to death. These diseases act in combination as HIV drives a decline in immunity while tuberculosis progresses due to defective immune status. This condition becomes more severe in case of multi-drug (MDRTB) and extensively drug resistant TB (XDRTB), which are difficult to treat and contribute to increased mortality. Tuberculosis can occur at any stage of HIV infection. The risk and severity of tuberculosis increases soon after infection with HIV. A study on gold miners of South Africa revealed that the risk of TB was doubled during the first year after HIV seroconversion. Although tuberculosis can be a relatively early manifestation of HIV infection, it is important to note that the risk of tuberculosis progresses as the CD4 cell count decreases along with the progression of HIV infection. The risk of TB generally remains high in HIV-infected patients, remaining above the background risk of the general population even with effective immune reconstitution and high CD4 cell counts with antiretroviral therapy.
Integrin α4β7 is an integrin heterodimer composed of CD49d (alpha-4) subunit and beta-7 subunit noncovalently linked. LPAM-1 is expressed on the cell surface of leukocytes. This receptor is involved in lymphocyte trafficking pathway to site of inflammation in intestinal tissues.