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
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