Trichomoniasis & Vibriosis Flashcards
What is the etiological agent of Trichomoniasis and route of transmission?
Tritrichomonas foetus subspecies fetus, which is motile flagellated protozoa that when a trophozoite form will have one anterior and three posterior flagella and undulating membrane that are characteristic. The major route of transmission of Trichomoniasis is venereal.
What are clinical signs of trichomoniasis?
In cows first trimester abortion, purluntent vaginal discharge, pyometra, and infertility, whereas bulls are assymptomatic with only mild balaposthitis reported to date.
How a sample be collected for diagnosis Trichomoniasis and what are the best diagnostic methods?
Trichomoniasis can be diagnosed in bulls by collection of smegma sample from deep crypts of the prepuce. Bulls should be sexually rested for week before collection. The sample can be collected using a pipete attach to a syringe that is introduced in prepuce and scrapped vigorously at the same time that pressure is applied to the syringe. Specific tools to perform the prepucial scraping called the Trichit In the US and Tricamper in Australia are available to be used. In Iowa, some studies also investigated using a wet gauze in the exposed prepuce during penile erection and protrusion at breeding soundness exam. It results revealed similar efficacy that the previous method described. Once the sample or gauze for the latter method mentioned is collected it has to be placed immediately on proper diamond modified media called In Pouch TF and place on envelope hidden of light and temperature between 20 and 37 C until sample is placed on incubator or send to be analyzed. Many laboratories will perform culture and PCR combined to increase the odds of successfully finding the protozoa. Culture will be read each 24 hours up to 6 days after collection. The sensitivity of combined test is ~80% . Trichomoniasis is reportable in many states and non-virgin bulls are required to have a negative PCR or PCR and cultured combined to be able to cross the frontiers of these states. The states requirement have limitations and owner need to be made aware of these limitations when making a decision about their bulls. The gold standard for Trichomoniasis in AI industry has been 6 weekly culture, but a combination of serial culture and PCR can be considered to improve test results.
In cows the long pipete or devices described above can be used to aspirated uterine and vaginal discharge for diagnosis. Once sample collected the same procedure described above for bulls should be implemented.
What are the methods for controlling Trichomoniasis in beef herd?
The first step on controlling Trichomoniasis in a beef herd is to identify bulls that positive and cull these bulls. Negative old bulls likely should be replaced because they are risks for false negative and older bulls seem more susceptible and unlikely to clear the infection than young bulls. Replace the bulls with young tested negative bulls of reputable source. Cows that aborted or ended the breeding season open should be culled. Cow that are pregnant should be segregate in a group pregnant less than 5 months or later than 5 months because cows that have older pregnancy are unlikely to loose the pregnancy. If a large group of open cows in the middle of breeding season remains open an alternative is to remove the bulls and test a subset of the groups and for the remain negative cows perform timed artificial insemination. Indeed, perform artificial insemination for an entire breeding season before use natural service again might be safer strategy to guarantee that cows are able to clear the infection and develop immunity. Unfortunately, immunity can be short lived and cows might become infected again if exposed. Vaccination of cows With TrichGuard is recommended because it will reduce the odds of cows become infected or the manifestation of clinical signs, but the vaccine does not fully protect cows against the Tritrichomonas. Cows should be vaccinated twice before the breeding season an again once a year. In the past, vaccination for bulls was not recommended, but a recent study by Cobo and colleagues suggest that bulls vaccination actually would reduce the odds fo bulls become contaminated.
What is etiological agent and route of transmission for Campylobacteriosis in cattle?
The etiological agent is Campylobacter fetus subspecies venerealis, which a single cell Gram-negative bacteria that appear in comma-shaped or s-shaped with “seagull wings” silhouette. It requires a microaerofilic environment to grow.
The mais route of transmission is venereal, but Campylobacteriosis might pass from bull to bull if the materials used for semen collection are not properly cleaned between collections. The same can said for AI equipment, so if it is not properly cleaned it can lead to cross contamination between cows. Bull to bull transmission because of bedding contamination has also been reported.
What are the clinical signs of Campylobacteriosis (Vibriosis)?
The clinical signs o Campylobacteriosis in cows are early embryonic death (Mostly between 30 and 70 days), poor conception rates, infertility, long interbreeding intervals, prolonged calving season, reduced calf crop, and poor reproductive performance. In addition severe placentitis and fetal hypoxia have been reported. Some of pathologies reported include cervicitis, endometritis, and salpingitis. Cows contaminated with the bacteria are capable of developing an immunity, clear the infection, and return to normal fertility between 4-8 months. Different than bull, cows will develop a strong immunity in the vagina and uterus producing IgG that help opsonize the bacteria for phagocytosis and IgA that helps immobilize the bacteria and block adherence. Conversely, IgA might also cause block of opsonization and prolonged presence of the bacteria.
What are the strategies to control Campylobacteriosis?
The number one strategy to control Campylobacteriosis is a strict vaccination program. Cows in a herd using natural service or simply exposed at any point to bulls need to be vaccinated twice before exposure to the bulls. The second vaccination need to occurs 3 weeks before exposure to allow proper specific immunity development. The first vaccine might be administered 2 months before the first vaccine. There are many bacterin vaccines available including oil-adjuvanted and aluminum hydroxide-absorbed. Oil-adjuvanted vaccines work better (longer duration of immunity and protection for a single dose), but might cause granulomas on the skin. Bulls should be vaccinated as well twice before starting to be used at 4 and 8 weeks before breeding cows. It is noteworthy that before introduction of the disease on a herd, vaccination is effective, however, after having the bacteria in the herd measures such as testing and culling positive bulls, culling open cows after the end of the breeding season, culling cows that aborted, segregation of early and late pregnant cows, and purchased of animals that are adequately immunized should aid on controlling the issues caused by Trichomoniasis. Implementation of AI should allow time for development of immunity. Immunotherapy with oils-adjuvanted vaccine has been the main form of treatment used.
What are the method for sample collection and diagnosis of Campylobacteriosis?
The method for sample collection in bulls involve to collect a smegma sample using a pipete attached to syringe. The sample should be place in specific transport enrich media (TEM) such as Clark’s media or Cary-Blair media until transported for the laboratory for analysis. To maximize success the transportation should be performed within 6 hours of collection. The major methods of diagnosis focus on identification of antigen of the bacteria rather than antibody for bulls. Antibody can be useful for detection of the organism in the cow. The major methods used by laboratories to identify antigens are fluorescent antibody test (93% sensitivity and 89% specificity) and IHC (94% sensitivity). Systemic antibody response is not helpful, because it might be due to non pathogenic bacteria. In cows, a vaginal mucous antibody agglutination test was developed, but because of its low sensitivity (~70%) is only used for screening herds. ELISA methods were developed to evaluate efficacy of immunizations. In cases of abortion fetal abomasal contents using darkfield microscopy and Gram staining may be useful. PCR can be used to differentiate the subspecies of Campylobacter (fetus vs venerealis)
