Review/Oorsig Volume 23, Issue 02 - Page 13

Volume 23 • Issue 02 • 2019 (18.7%) of all samples, goats having higher rates of co-infection compared to sheep. Phylogenetic tree analysis sequence of pCS20 gene of Erlichia ruminantium of this study was found to be in the same clade with Kumm2 and Riverside strains both from South Africa. The phylogram of SSU rRNA of Theileria ovis had longer branch length compared to all other sequences most of which were from Asia and Middle East. This study provides important data for understanding the tick-borne diseases occurrence in the study area and it is expected to improve the approach for the diagnosis and control of these diseases. AF – 28 November 2017 We do see clinical Anaplasma ovis cases in the Eastern Cape periodically – communal and sometimes commercial farms. (from Sterkstroom, Ida/Elliot, Tarkastad, Cofimvaba that I can recall). Glenn Burroughs described the so-called “ill-thrift syndrome” in the E. Cape some 30-40 years ago. Usually seen from August to November (related to nutritional and weaning stress I suspect) – saw a case last week in fact. Unweaned lambs die fairly acutely with what would be typical gallsickness in cattle – severe icterus and anaemia, splenomegally etc. Blood smears have 80-90% parasitaemia, often with multiple parasites in each rbc – typical Anaplasma marginale smears. Diff-quick® works fine. Giemsa is better for the other parasites associated with it (Theileria ovis and Epyrithrozoon ovis). I had an outbreak in weaned merino lambs in Sterkstroom a few years back – extremely anaemic, no icterus in this case, no Haemonchus on post mortems (he dosed repeatedly with Derquantel and caused the first anthelmintic resistance I had seen just after the drug was launched). Smears were full of Anaplasma ovis parasites. Blanket treatment with oxytetracycline stopped the outbreak, no cases since on the farm that I am aware of. A. ovis, T. ovis and E. ovis all have Rhipicephalus evertsi as the vector – most common tick on sheep hereabouts, and apparently needs all three parasites to be present with a stress situation for clinical cases to occur. Usually parasites are non-pathogenic individually. We did have the parasites identified on blood samples at the time. I think the main reason it is not diagnosed more commonly is that we don’t do blood smears often enough from sheep! GB – 28 November 2017 Anaplasma ovis has been known and identified here for decades, but because it is seldom recognised as a clinical disease, it often goes undiagnosed and thus also unreported. It sometimes causes mild icterus in lambs and this is only picked up at slaughter in otherwise perfect carcasses. May be related to stress prior to slaughter? JvR – 29 November 2017 I have seen outbreaks of Anaplasmosis in young lambs a few days after taildocking with an emasculator. At the time I suggested that it was a mechanical transmission, but it could also have been stress. The other parasites may have been involved as well. Other outbreaks seemed more stress related. They were mostly lambs on irrigated pastures where Rhipicephalus evertsi is found more commonly than in natural pasture. Q-fever in adult ewes also had me confused with A. ovis in one outbreak because of jaundice in some cases but the blood smears were negative. Erasmus found Eperythrozoon and trace element problems in ill-thrift in Albany if my memory serves me correctly. Theileria is often seen in smears of normal animals. I also never saw cases following the first outbreak and treatment on a farm. We also do not see Bovine anaplasmosis any more, in spite of the massive increase in cattle population. PR – 30 November 2017 - With the mentioned co-infection of pathogens and goats having higher rates of co-infection, will this tend to make goats especially, but sheep too, more prone to heartwater infections showing clinical signs? In some areas here in Kwa-Zulu Natal there are indigenous goats dying in high numbers, in heartwater stable areas, (Msinga/Tugela Ferry) that were born there. Although people still like to block with Terramycin too, nothing seems to halt it. Deaths occur right through the year. Very dry and hot sweetveld area. Might this not lead to more of or a better understanding of deaths due to heartwater? How common is Babesia ovis in SA then? Should we consider blocking or treating with Babesia remedies too, to increase our success? So, where A. ovis or B. ovis on its own do not cause signs, co-infection might? List of Contributors AF – Dr Alan Fisher AvZ – Dr Albert van Zyl DM – Dr Dave Midgley DO – Dr Danie Odendaal DR – Dr Diethardt Rodenwoldt GB – Prof Gareth Bath JvN – Dr Jean van Niekerk JvR – Dr Johan van Rooyen MH – Dr Maryke Henton MvV – Dr Moritz van Vuuren PR – Dr Paul Reynolds 13