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Definite diagnosis of brucellosis requires the isolation of the organism from the blood, body fluids, or tissues, but serological methods may be the only tests available in many settings. Positive blood culture yield ranges between 40% and 70% and is less commonly positive for "B. abortus" than "B. melitensis" or "B. suis". Identification of specific antibodies against bacterial lipopolysaccharide and other antigens can be detected by the standard agglutination test (SAT), rose Bengal, 2-mercaptoethanol (2-ME), antihuman globulin (Coombs’) and indirect enzymelinked immunosorbent assay (ELISA). SAT is the most commonly used serology in endemic areas. An agglutination titre greater than 1:160 is considered significant in nonendemic areas and greater than 1:320 in endemic areas. Due to the similarity of the O polysaccharide of "Brucella" to that of various other Gram-negative bacteria (e.g. "Francisella tularensis", "Escherichia coli", "Salmonella urbana", "Yersinia enterocolitica", "Vibrio cholerae", and "Stenotrophomonas maltophilia") the appearance of cross-reactions of class M immunoglobulins may occur. The inability to diagnose "B. canis" by SAT due to lack of cross-reaction is another drawback. False-negative SAT may be caused by the presence of blocking antibodies (the prozone phenomenon) in the α2-globulin (IgA) and in the α-globulin (IgG) fractions. Dipstick assays are new and promising, based on the binding of "Brucella" IgM antibodies, and found to be simple, accurate, and rapid. ELISA typically uses cytoplasmic proteins as antigens. It measures IgM, IgG, and IgA with better sensitivity and specificity than the SAT in most recent comparative studies. The commercial Brucellacapt test, a single-step immunocapture assay for the detection of total anti-"Brucella" antibodies, is an increasingly used adjunctive test when resources permit. PCR is fast and should be specific. Many varieties of PCR have been developed (e.g. nested PCR, realtime PCR and PCR-ELISA) and found to have superior specificity and sensitivity in detecting both primary infection and relapse after treatment. Unfortunately, these have yet to be standardized for routine use, and some centres have reported persistent PCR positivity after clinically successful treatment, fuelling the controversy about the existence of prolonged chronic brucellosis. Other laboratory findings include normal peripheral white cell count, and occasional leucopenia with relative lymphocytosis. The serum biochemical profiles are commonly normal.
According to a study published in 2002, an estimated 10–13% of farm animals are infected with "Brucella" species. Annual losses from the disease were calculated to be around 60 million dollars. Since 1932, government agencies have undertaken efforts to contain the disease. Currently, all cattle of ages 3–8 months is required to be given the "Brucella abortus" strain 19 vaccine.
Only specialized laboratories can adequately diagnose "Babesia" infection in humans, so "Babesia" infections are considered highly under-reported. It develops in patients who live in or travel to an endemic area or receive a contaminated blood transfusion within the preceding 9 weeks, so this aspect of the medical history is vital. Babesiosis may be suspected when a person with such an exposure history develops persistent fevers and hemolytic anemia. The definitive diagnostic test is the identification of parasites on a Giemsa-stained thin-film blood smear.
So-called "Maltese cross formations" on the blood film are diagnostic (pathognomonic) of babesiosis, since they are not seen in malaria, the primary differential diagnosis. Careful examination of multiple smears may be necessary, since "Babesia" may infect less than 1% of circulating red blood cells, thus be easily overlooked.
Serologic testing for antibodies against "Babesia" (both IgG and IgM) can detect low-level infection in cases with a high clinical suspicion, but negative blood film examinations. Serology is also useful for differentiating babesiosis from malaria in cases where people are at risk for both infections. Since detectable antibody responses require about a week after infection to develop, serologic testing may be falsely negative early in the disease course.
A polymerase chain reaction (PCR) test has been developed for the detection of "Babesia" from the peripheral blood. PCR may be at least as sensitive and specific as blood-film examination in diagnosing babesiosis, though it is also significantly more expensive. Most often, PCR testing is used in conjunction with blood film examination and possibly serologic testing.
Other laboratory findings include decreased numbers of red blood cells and platelets on complete blood count.
In animals, babesiosis is suspected by observation of clinical signs (hemoglobinuria and anemia) in animals in endemic areas. Diagnosis is confirmed by observation of merozoites on thin film blood smear examined at maximum magnification under oil using Romonovski stains (methylene blue and eosin). This is a routine part of the veterinary examination of dogs and ruminants in regions where babesiosis is endemic.
"Babesia canis" and "B. bigemina" are "large "Babesia" species" that form paired merozoites in the erythrocytes, commonly described as resembling "two pears hanging together", rather than the "Maltese cross" of the "small "Babesia" species". Their merozoites are around twice the size of small ones.
Cerebral babesiosis is suspected "in vivo" when neurological signs (often severe) are seen in cattle that are positive for "B. bovis" on blood smear, but this has yet to be proven scientifically. Outspoken red discoloration of the grey matter "post mortem" further strengthens suspicion of cerebral babesiosis. Diagnosis is confirmed "post mortem" by observation of "Babesia"-infected erythrocytes sludged in the cerebral cortical capillaries in a brain smear.
Diagnosis is usually based on serology (looking for an antibody response) rather than looking for the organism itself. Serology allows the detection of chronic infection by the appearance of high levels of the antibody against the virulent form of the bacterium. Molecular detection of bacterial DNA is increasingly used. Culture is technically difficult and not routinely available in most microbiology laboratories.
Q fever can cause endocarditis (infection of the heart valves) which may require transoesophageal echocardiography to diagnose. Q fever hepatitis manifests as an elevation of alanine transaminase and aspartate transaminase, but a definitive diagnosis is only possible on liver biopsy, which shows the characteristic fibrin ring granulomas.
The most frequent clinical sign following "B. suis" infection is abortion in pregnant females, reduced milk production, and infertility. Cattle can also be transiently infected when they share pasture or facilities with infected pigs, and "B. suis" can be transmitted by cow’s milk.
Swine also develop orchitis (swelling of the testicles), lameness (movement disability), hind limb paralysis, or spondylitis (inflammation in joints).
Protection is offered by Q-Vax, a whole-cell, inactivated vaccine developed by an Australian vaccine manufacturing company, CSL Limited. The intradermal vaccination is composed of killed "C. burnetii" organisms. Skin and blood tests should be done before vaccination to identify pre-existing immunity, because vaccinating people who already have an immunity can result in a severe local reaction. After a single dose of vaccine, protective immunity lasts for many years. Revaccination is not generally required. Annual screening is typically recommended.
In 2001, Australia introduced a national Q fever vaccination program for people working in “at risk” occupations. Vaccinated or previously exposed people may have their status recorded on the Australian Q Fever Register, which may be a condition of employment in the meat processing industry. An earlier killed vaccine had been developed in the Soviet Union, but its side effects prevented its licensing abroad.
Preliminary results suggest vaccination of animals may be a method of control. Published trials proved that use of a registered phase vaccine (Coxevac) on infected farms is a tool of major interest to manage or prevent early or late abortion, repeat breeding, anoestrus, silent oestrus, metritis, and decreases in milk yield when "C. burnetii" is the major cause of these problems.
Vaccines against anaplasmosis are available. Carrier animals should be eliminated from flocks. Tick control may also be useful although it can be difficult to implement.
Treatment of asymptomatic carriers should be considered if parasites are still detected after 3 months. In mild-to-moderate babesiosis, the treatment of choice is a combination of atovaquone and azithromycin. This regimen is preferred to clindamycin and quinine because side effects are fewer. The standard course is 7 to 10 days, but this is extended to at least 6 weeks in people with relapsing disease. Even mild cases are recommended to be treated to decrease the chance of inadvertently transmitting the infection by donating blood. In life-threatening cases, exchange transfusion is performed. In this procedure, the infected red blood cells are removed and replaced with uninfected ones.
Imizol is a drug used for treatment of babesiosis in dogs.
Extracts of the poisonous, bulbous plant "Boophone disticha" are used in the folk medicine of South Africa to treat equine babesiosis. "B. disticha" is a member of the daffodil family Amaryllidaceae and has also been used in preparations employed as arrow poisons, hallucinogens, and in embalming. The plant is rich in alkaloids, some of which display an action similar to that of scopolamine.
Because "B. suis" is facultative and intracellular, and is able to adapt to environmental conditions in the macrophage, treatment failure and relapse rates are high. The only effective way to control and eradicate zoonosis is by vaccination of all susceptible hosts and elmination of infected animals. The "Brucella abortus" (rough LPS "Brucella") vaccine, developed for bovine brucellosis and licensed by the USDA Animal Plant Health Inspection Service, has shown protection for some swine and is also effective against "B. suis" infection, but currently no approved vaccine for swine brucellosis is available.
However, simple husbandry changes and practical midge control measures may help break the livestock infection cycle. Housing livestock during times of maximum midge activity (from dusk to dawn) may lead to significantly reduced biting rates. Similarly, protecting livestock shelters with fine mesh netting or coarser material impregnated with insecticide will reduce contact with the midges. The "Culicoides" midges that carry the virus usually breed on animal dung and moist soils, either bare or covered in short grass. Identifying breeding grounds and breaking the breeding cycle will significantly reduce the local midge population. Turning off taps, mending leaks and filling in or draining damp areas will also help dry up breeding sites. Control by trapping midges and removing their breeding grounds may reduce vector numbers. Dung heaps or slurry pits should be covered or removed, and their perimeters (where most larvae are found) regularly scraped.
Treatment usually involves a prescription of doxycycline (a normal dose would be 100 mg every 12 hours for adults) or a similar class of antibiotics. Oxytetracycline and imidocarb have also been shown to be effective. Supportive therapy such as blood products and fluids may be necessary.
Diagnosis of BMCF depends on a combination of history and symptoms, histopathology and detection in the blood or tissues of viral antibodies by ELISA or of viral DNA by PCR. The characteristic histologic lesions of MCF are lymphocytic arteritis with necrosis of the blood vessel wall and the presence of large T lymphocytes mixed with other cells. The similarity of MCF clinical signs to other enteric diseases, for example blue tongue, mucosal disease and foot and mouth make laboratory diagnosis of MCF important. The world organisation for animal health recognises histopathology as the definitive diagnostic test, but laboratories have adopted other approaches with recent developments in molecular virology. No vaccine has as yet been developed.
Outbreaks in southern Europe have been caused by serotypes 2 and 4, and vaccines are available against these serotypes (ATCvet codes: for sheep, for cattle). However, the disease found in northern Europe (including the UK) in 2006 and 2007 has been caused by serotype 8. Vaccine companies Fort Dodge Animal Health (Wyeth), Merial and Intervet were developing vaccines against serotype 8 (Fort Dodge Animal Health has serotype 4 for sheep, serotype 1 for sheep and cattle and serotype 8 for sheep and cattle) and the associated production facilities. A vaccine for this is now available in the UK, produced by Intervet. Fort Dodge Animal Health has their vaccines available for multiple European Countries (vaccination will start in 2008 in Germany, Belgium, Switzerland, Spain and Italy). However, immunization with any of the available vaccines preclude later serological monitoring of affected cattle populations, a problem which could be resolved using next-generation subunit vaccines currently in development.
In January 2015, Indian researchers launched its vaccine. Named 'Raksha Blu', it will protect the animals against five strains of the ‘bluetongue’ virus prevalent in the country.
Antibody (Ig) ELISAs are used to detect historical BVDV infection; these tests have been validated in serum, milk and bulk milk samples. Ig ELISAs do not diagnose active infection but detect the presence of antibodies produced by the animal in response to viral infection. Vaccination also induces an antibody response, which can result in false positive results, therefore it is important to know the vaccination status of the herd or individual when interpreting results. A standard test to assess whether virus has been circulating recently is to perform an Ig ELISA on blood from 5–10 young stock that have not been vaccinated, aged between 9 and 18 months. A positive result indicates exposure to BVDV, but also that any positive animals are very unlikely to be PI animals themselves. A positive result in a pregnant female indicates that she has previously been either vaccinated or infected with BVDV and could possibly be carrying a PI fetus, so antigen testing of the newborn is vital to rule this out. A negative antibody result, at the discretion of the responsible veterinarian, may require further confirmation that the animal is not in fact a PI.
At a herd level, a positive Ig result suggests that BVD virus has been circulating or the herd is vaccinated. Negative results suggest that a PI is unlikely however this naïve herd is in danger of severe consequences should an infected animal be introduced. Antibodies from wild infection or vaccination persist for several years therefore Ig ELISA testing is more valuable when used as a surveillance tool in seronegative herds.
Antigen ELISA and rtPCR are currently the most frequently performed tests to detect virus or viral antigen. Individual testing of ear tissue tag samples or serum samples is performed. It is vital that repeat testing is performed on positive samples to distinguish between acute, transiently infected cattle and PIs. A second positive result, acquired at least three weeks after the primary result, indicates a PI animal. rtPCR can also be used on bulk tank milk (BTM) samples to detect any PI cows contributing to the tank. It is reported that the maximum number of contributing cows from which a PI can be detected is 300.
Although no specific treatment for acute infection with SuHV1 is available, vaccination can alleviate clinical signs in pigs of certain ages. Typically, mass vaccination of all pigs on the farm with a modified live virus vaccine is recommended. Intranasal vaccination of sows and neonatal piglets one to seven days old, followed by intramuscular (IM) vaccination of all other swine on the premises, helps reduce viral shedding and improve survival. The modified live virus replicates at the site of injection and in regional lymph nodes. Vaccine virus is shed in such low levels, mucous transmission to other animals is minimal. In gene-deleted vaccines, the thymidine kinase gene has also been deleted; thus, the virus cannot infect and replicate in neurons. Breeding herds are recommended to be vaccinated quarterly, and finisher pigs should be vaccinated after levels of maternal antibody decrease. Regular vaccination results in excellent control of the disease. Concurrent antibiotic therapy via feed and IM injection is recommended for controlling secondary bacterial pathogens.
One study using the medicinal plant "Peganum harmala" showed it to have a lifesaving effect on cattle infected with East Coast fever.
The classical treatment with tetracyclines (1970–1990) cannot provide efficiency more than 50%.
Since the early 1990s, buparvaquone is used in bovine theileriosis with remarkable results (90 to 98% recovery).
Other than the buparvaquones, other chemotherapeutic options are the parvaquones, e.g. Clexon. Halofuginone lactate has also been shown to have an 80.5% efficacy against "Theirelia parva parva" infections. The ultimate factor that causes death is pulmonary edema.
In May 2010, a vaccine to protect cattle against East Coast fever reportedly had been approved and registered by the governments of Kenya, Malawi and Tanzania. This consists of cryopreserved sporozoites from crushed ticks, but it is expensive and can cause disease.
Control of the disease relies on control of ticks of domestic animals, particularly disease-resistant ticks. This is a major concern in tropical countries with large livestock populations, especially in the endemic area. Pesticides (acaricides) are applied in dipping baths or spray races, and cattle breeds with good ability to acquire immune resistance to the vector ticks are used.
A ban on feeding meat and bone meal to cattle has resulted in a strong reduction in cases in countries where the disease was present. In disease-free countries, control relies on import control, feeding regulations, and surveillance measures.
In UK and US slaughterhouses, the brain, spinal cord, trigeminal ganglia, intestines, eyes, and tonsils from cattle are classified as specified risk materials, and must be disposed of appropriately.
An enhanced BSE-related feed ban is in effect in both the United States and Canada to help improve prevention and elimination of BSE.
The use of a seven-way clostridial vaccination is the most common, cheapest, and efficacious preventative measure taken against blackleg. Burning the upper layer of soil to eradicate left-over spores is the best way to stop the spread of blackleg from diseased cattle. Diseased cattle should be isolated. Treatment is generally unrewarding due to the rapid progression of the disease, but penicillin is the drug of choice for treatment. Treatment is only effective in the early stages and as a control measure.
Dr. Oliver Morris (O.M.) Franklin made a significant contribution to the welfare of cattle and the livestock industry with his development of the blackleg vaccine. Franklin developed the original method of giving the vaccine while at Kansas State Agriculture College using live cattle. Franklin and another graduate veterinarian founded the original Kansas Blackleg Serum Co. in Wichita in 1916.
When infection begins, the animal may develop a fever, and the affected limb can feel hot to the touch. The limb usually swells significantly, and the animal can develop lameness on the affected leg. Crepitation (the sensation of air under the skin) can be noticed in many infections, as the area seems to crackle under pressure.
Once clinical signs develop, the animal may only live a short while, sometimes as few as 12 hours. Occasionally, cattle succumb to the disease without showing any symptoms, and only a necropsy reveals the cause. During a necropsy, a diagnosis is usually made very quickly, as the affected muscle is usually mottled with black patches, which are dead tissue, killed by the toxins the bacteria release when they infect live tissue. If viewed under a microscope, small rod-like bacteria can be seen to confirm the diagnosis.
Diagnosis of BSE continues to be a practical problem. It has an incubation period of months to years, during which no symptoms are noticed, though the pathway of converting the normal brain prion protein (PrP) into the toxic, disease-related PrP form has started. At present, virtually no way is known to detect PrP reliably except by examining "post mortem" brain tissue using neuropathological and immunohistochemical methods. Accumulation of the abnormally folded PrP form of PrP is a characteristic of the disease, but it is present at very low levels in easily accessible body fluids such as blood or urine. Researchers have tried to develop methods to measure PrP, but no methods for use in materials such as blood have been accepted fully.
The traditional method of diagnosis relies on histopathological examination of the medulla oblongata of the brain, and other tissues, "post mortem". Immunohistochemistry can be used to demonstrate prion protein accumulation.
In 2010, a team from New York described detection of PrP even when initially present at only one part in a hundred billion (10) in brain tissue. The method combines amplification with a novel technology called surround optical fiber immunoassay and some specific antibodies against PrP. After amplifying and then concentrating any PrP, the samples are labelled with a fluorescent dye using an antibody for specificity and then finally loaded into a microcapillary tube. This tube is placed in a specially constructed apparatus so it is totally surrounded by optical fibres to capture all light emitted once the dye is excited using a laser. The technique allowed detection of PrP after many fewer cycles of conversion than others have achieved, substantially reducing the possibility of artifacts, as well as speeding up the assay. The researchers also tested their method on blood samples from apparently healthy sheep that went on to develop scrapie. The animals’ brains were analysed once any symptoms became apparent. The researchers could, therefore, compare results from brain tissue and blood taken once the animals exhibited symptoms of the diseases, with blood obtained earlier in the animals’ lives, and from uninfected animals. The results showed very clearly that PrP could be detected in the blood of animals long before the symptoms appeared. After further development and testing, this method could be of great value in surveillance as a blood- or urine-based screening test for BSE.
On post-mortem examination (necropsy), the most obvious gross lesion is subcutaneous oedema in the submandibular and pectoral (brisket) regions. Petechial haemorrhages are found subcutaneously and in the thoracic cavity. In addition, congestion and various degrees of consolidation of the lung may occur. Animals that die within 24–36 hours, have only few petechial haemorrhages on the heart and generalised congestion of the lung, while in animals that die after 72 hours, petechial and ecchymotic haemorrhages were more evident and lung consolidation are more extensive.
Haemorrhagic septicaemia is one of the most economically important pasteurelloses. Haemorrhagic septicaemia in cattle and buffaloes was previously known to be associated with one of two serotypes of "P. multocida": Asian B:2 and African E:2 according to the Carter-Heddleston system, or 6:B and 6:E using the Namioka-Carter system.
The disease occurs mainly in cattle and buffaloes, but has also been reported in goats ("Capra aegagrus hircus"), African buffalo ("Syncerus nanus"), camels, horses and donkeys ("Equus africanus asinus"), in pigs infected by serogroup B, and in wild elephants ("Elephas maximus"). Serotypes B:1 and B:3,4 have caused a septicaemic disease in antelope ("Antilocapra americana") and elk ("Cervus canadensis"), respectively. Serotype B:4 was associated with the disease in bison ("Bison bison").
Serotypes E:2 and B:2 were associated with HS outbreaks in Africa and Asia respectively. Serotype E:2 was reported in Senegal, Mali, Guinea, Ivory Coast, Nigeria, Cameroon, the Central African Republic and Zambia. However, it is now inaccurate to associate outbreaks in Africa with serotype E:2 as many outbreaks of HS in Africa have now been associated with serogroup B. In the same manner, serogroup E has been associated with outbreaks in Asia. For instance, one record of "Asian serotype" (B:2) was reported in Cameroon. Some reports showed that serotype B:2 may be present in some East African countries. Both serogroups B and E have been reported in Egypt and Sudan.
Natural routes of infection are inhalation and/or ingestion. Experimental transmission has succeeded using intranasal aerosol spray or oral drenching. When subcutaneous inoculation is used experimentally, it results in rapid onset of the disease, a shorter clinical course and less marked pathological lesions compared to the longer course of disease and more profound lesions of oral drenching and the intranasal infection by aerosols.
When HS was introduced for the first time into a geographic area, morbidity and mortality rates were high, approaching 100% unless animals were treated in the very early stages of disease.
East Coast fever (theileriosis) is an animal disease in Africa caused by the protozoan parasite "Theileria parva". It excludes diseases caused by other "Theileria"
SuHV1 can be used to analyze neural circuits in the central nervous system (CNS). For this purpose the attenuated (less virulent) Bartha SuHV1 strain is commonly used and is employed as a retrograde and anterograde transneuronal tracer. In the retrograde direction, SuHV1-Bartha is transported to a neuronal cell body via its axon, where it is replicated and dispersed throughout the cytoplasm and the dendritic tree. SuHV1-Bartha released at the synapse is able to cross the synapse to infect the axon terminals of synaptically connected neurons, thereby propagating the virus; however, the extent to which non-synaptic transneuronal transport may also occur is uncertain. Using temporal studies and/or genetically engineered strains of SuHV1-Bartha, second, third, and higher order neurons may be identified in the neural network of interest.