Experimental Eperythrozoon ovis infection of sheep

Review of clinical aspects, epidemiology and diagnosis of haemotropic Mycoplasma ovis in small ruminants: current status and future perspectives in tropics focusing on Malaysia

Mycoplasma ovis (formerly Eperythrozoon ovis) is an epierythrocytic parasitic bacterium of small ruminants known as haemotropic mycoplasma, which is transmitted mechanically by biting flies and contaminated instruments. Acute mycoplasmosis causes severe haemolytic anaemia and mortality in young animals. At the same time, chronic disease may produce mild anaemia and varying degrees of morbidity depending on several factors, including age, reproductive status, the plane of nutrition, immunological status and the presence of concurrent infection. Haemotropic Mycoplasma ovis is currently recognised as an emerging zoonotic pathogen which is widely distributed in the sheep and goat producing areas of tropics and subtropics, where the disease is nearly endemic. Human infection has been reported in pregnant women, immunocompromised patients and people exposed to animals and arthropods. The current diagnosis of haemoplasma relies on microscopic evaluation of Giemsa-stained blood smear and PCR. Although there are few published reports on the incidence of haemotropic Mycoplasma ovis infection of small ruminants in Malaysia, information on its prevalence, risk factors, severity and economic impacts is grossly inadequate. Therefore, a large-scale survey of small ruminant flocks is necessary to elucidate the current seroprevalence status and molecular characteristics of haemotropic M. ovis infection in Malaysia using ELISA and PCR sequencing technologies. In the future, surveillance programs, including vector forecast, quarantine, monitoring by periodic surveys and public enlightenment, will limit the internal and transboundary spread of M. ovis, enhance control efforts and mitigate production losses in Malaysia.

Mycoplasma ovis infection in domestic sheep (Ovis aries) in the United States: Prevalence, distribution, associated risk factors, and associated outcomes

Mycoplasma ovis is a hemotropic bacterium reported to infect sheep, goats, and deer species. Infection in these species can result in anemia, jaundice, and ill-thrift. Although of worldwide distribution, only rare reports of this bacterium in the United States exist. The objectives of this retrospective study were to identify the prevalence and distribution of M. ovis, and identify associated demographic and management risk factors, and reproductive and production outcomes associated with infection on domestic sheep (Ovis aries) operations in the United States. As part of the United States Department of Agriculture (USDA), Animal Plant Health Inspection Service, Veterinary Services' National Animal Health Monitoring System (NAHMS) Sheep 2001 and 2011 studies, blood was collected and sera banked from 21,369 ewes in 2001 and 13,128 ewes in 2011. Participating premises were located in 22 states across the United States for each sample year. In 2015 the USDA, Agricultural Research Service, Animal Disease Research Unit received aliquots of these sera, and DNA was extracted and analyzed by PCR for the presence of M. ovis genomic DNA. Flock presence and mean within-flock prevalence of M. ovis were 73.3% and 23.2%, respectively. Model selection using Mallow's C_p Criterion was used to determine which variables significantly affected flock presence and within-flock prevalence. The final flock presence model included flock size, year of blood collection, region, and vaccine administration. The final within-flock prevalence model included year of blood collection, interaction between flock size and region, and interaction between reported abortions and grazing with sheep from other operations. Medium and large operations had a higher flock presence and within-flock prevalence. Flock presence was higher in operations that administered any vaccines. Operations that reported any abortions and grazed with sheep from other operations had a higher within-flock prevalence.

Chemotherapeutic efficacy of imidocarb dipropionate on experimental Eperythrozoon ovis infection in sheep

Non-splenectomised Cheviot and Soay sheep experimentally infected with Eperythrozoon ovis were treated subcutaneously with two doses of 4 mg/kg of imidocarb dipropionate 24 hours apart. A rapid reduction in E. ovis parasitaemias following the first injection of imidocarb was observed and E. ovis organisms were not demonstrable 48 hours after the first treatment. However, recrudescences of infection were observed 14 and 28 days after treatment in the Soay and Cheviot sheep respectively. Side-effects associated with treatment were registered in the Cheviot sheep but not in the Soay sheep.

Tick-borne diseases of domestic animals in northern Nigeria. II. Research summary, 1966 to 1976

During the first 10 years of its existence, the Department of Parasitology and Entomology of the Faculty of Veterinary Medicine, Ahmadu Bello University in Zaria, Nigeria, confirmed or described for the first time the occurrence of 25 different tick-borne parasites of domestic animals in the northern part of the country. Most of these organisms occur as inapparent infections but may serve as complicating factors in any adverse host condition. The transmission of Babesia bigemina by Boophilus decoloratus, Cowdria ruminantium by Amblyomma variegatum, and Borrelia anserina and Aegyptianella pullorum by Argas persicus was confirmed under Nigerian conditions.