出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/08/08 10:32:43」(JST)
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Tritrichomonas foetus is a single celled flagellated protozoan parasite that is known to be a pathogen of the bovine reproductive tract as well as the intestinal tract of cats. In cattle, the organism is transmitted to the female vagina and uterus from the foreskin of the bull where the parasite is known to reside. It causes infertility, and, at times, has caused spontaneous abortions in the first trimester. Cases of infection in cattle have declined due to the use of artificial insemination. In the last ten years, there have been reports of Tritrichomonas foetus in the feces of young cats that have diarrhea and live in households with multiple cats.
Tritrichomonas foetus in the genus Tritrichomonas within the order Trichomonadida in the Kingdom Protoctista. The parasite is 5-25 µm in size and is spindle shaped with four flagella which are whiplike projections and an undulating or wavy membrane. Their movement is jerky and in a forward direction, and they also do "barrel rolls". The organisms look like small tadpoles with small tails when viewed microscopically. The parasite interacts with bacteria that normally reside in the intestinal tract by adhering to the intestinal epithelium of the host.
Bulls do not show any clinical signs of infections and can infect females at mating. In cows, there may be infertility, embryonic death and abortion, and reproductive tract infections such as pyometra.[1][2]
In cats, Tritrichomonas foetus is characterized by diarrhea that comes and goes and may contain blood and mucus at times. The diarrhea is semi formed in a cow pie consistency. In most cases it affects cats of 12 months of age or younger and cats from rescue shelters and homes with multiple cats. Close and direct contact appears to be the mode in which the parasite is transmitted. Tritrichomonas foetus is most common in purebred felines, breeds like Bengals, Persians, etc. Since catteries tend to trade queens and studs to provide greater genetic diversity, the parasite can be spread from one cattery to another. One easy way Tritrichomonas foetus can be differentiated from other common diarrhea is that is extremely malodorous.[citation needed]
In cattle, a presumptive diagnosis can be made from the signs of infertility and geography. Diagnosis may rely on microscopic examination of vaginal or preputial smears. Complement fixation can be performed to detect parasite antibodies in vaginal secretions.[2]
In cats, Tritrichomonas foetus can be detected by two methods:
In cattle, bulls can receive topical treatment with acriflavine. Bulls may be culled if treatment is ineffective. Cows can be vaccinated against the parasite. Artificial insemination may help reduce the venereal transmission and prevalence of the disease.[2]
Treatment of the infection is difficult due to drug resistance. Traditional antiprotozoal drugs such as fenbendazole and metronidazole do not alleviate the symptoms. Some antimicrobial drugs have been shown to improve symptoms but do not eradicate the parasite.
Dr. Jody Gookin at North Carolina State University, College of Veterinary Medicine, has published research on the effectiveness of the drug ronidazole.[4][5] Currently there is no drug specifically indicated for T. foetus in felines, and ronidazole treatment is considered an off-label use. Ronidazole has had good efficacy in eradiation of the parasite in felines. Care should be used when administering the drug. Exact dosing is essential, and caplets are recommended over suspension to increase dose accuracy. Additionally, ronidazole has the potential for a variety of side effects, most importantly, neurological side effects. During treatment, the cat should be engaged in play activity regularly to ensure they are not experiencing neurological side effects, or motor skills impairment. Two weeks of ronidazole, 30 mg/kg, once daily, is currently the recommended dosage. Care should be exercised while handling ronidazole, which is toxic to humans.[citation needed]
During treatment, the feline should be keep isolated from other cats as to prevent the spread to another cat (typically transmitted by an infected cat sharing the same litter box as other cats). The cat should be fed a veterinarian prescribed dry-food diet, preferably of high fiber content. Wet food should be avoided. A common GI diet remedy in cats (boiled chicken breast, white rice, and pumpkin) may be highly beneficial during and after treatment.
It has been shown that most cats show improvement and no signs of infection within 2 years of onset. It appears that over time the parasite dies off and the infection is remedied on its own. In some cases, the symptoms may improve over time, but the animal is likely to still be a carrier of the parasite, capable of transmitting it to another cat.
Treatment with ronidazole has shown good efficacy, and some positive results may be achieved after just two to three days of treatment, but completion of the two week cycle of drugs to avoid the risk of recurrence. It is essential that a PCR test be conducted after treatment to verify that the organism has been completely eradicated. It is also recommended that a follow-up test be performed a few months after the first.
During and after treatment a special diet may be required. Since the organism resides in the colon of the feline, long-term infection may cause excessive damage to the colon. A special diet may be required for several months, depending on the length and severity of infection.
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| リンク元 | 「ウシ胎仔トリコモナス」 |
| 関連記事 | 「foetus」「Tritrichomonas」 |