Monday, July 9, 2018

PRO/AH/EDR> Neospora caninum, bovine - UK (02): (Wales) spread, preventn, cntrl, comment,RFI

NEOSPORA CANINUM, BOVINE - UK (02): (WALES) SPREAD, PREVENTION,
CONTROL, COMMENT, REQUEST FOR INFORMATION
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Date: Sat 7 Jul 2018
From: Fabio Del Piero <fdelpiero@lsu.edu> [edited]


Re: ProMED-mail post Neospora caninum, bovine - UK: (Wales), spread,
prevention http://promedmail.org/post/20180706.5891156
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It would be interesting to know how these _Neospora_ abortion storms
were diagnosed. Being vertically transmitted organisms, PCR on the
fetus and serology on the dams only indicate the contact with the
agent and, for PCR, the presence of the organism in the fetus. We also
wonder if the fetuses were evaluated for the presence of BVDV [Bovine
viral diarrhea virus], which in the past was present in aborted
fetuses with _Neospora_.

The gold standard remains the complete histologic evaluation of the
fetus to detect the suggestive and pathognomonic lesions within fetal
brain, heart, skeletal muscle, tongue; often associated with
nephritis, hepatitis and placentitis.

--
Prof. Fabio Del Piero, DVM, PhD, Dipl. ACVP
Pathobiological Sciences, Louisiana State University,
USA
<fdelpiero@lsu.edu>

[Information on the techniques applied in Wales for the diagnosis of
the described _Neospora_ abortions in cattle, as requested by Prof Del
Piero, will be appreciated.

The following comments have been received from Prof Eugene Pipano,
DVM, PhD, Koret School of Veterinary Medicine, Hebrew University,
Israel:

1. If _Neospora caninum_ parasites are detected in the aborted fetuses
they cannot be considered as commensal organism. _Neospora_
tachyzoites multiplying in the fetus always cause some degree of
damage. The question remains whether the abortions were caused by
_Neospora_ alone or by the concurrent effect of _Neospora_ and the BVD
virus. Histopathological examination may contribute to the answer.

2. The statement: " ..._Neospora_ does not harm dogs..." is inexact.
_Neospora caninum_ may cause in dogs neurological symptoms (paresis,
paralysis, ataxia) myositis and numerous dermal cysts containing
bradyzoites.

Drs. Del Piero and Pipano are gratefully acknowledged for their
comments.

The following data on _Neospora_ control schemes in dairy farms, as
applied in some countries, were presented in a 2016 review paper (Ref
1; references omitted).

1. Netherlands:
Approximately 4000 dairy farmers participate in a control programme
that consists of regular quarterly bulk milk screening, serological
investigation of the aborting dams, and progressive culling of
seropositive cows. In herds with negative bulk milk tests and no
abortion problems, testing of purchased stock is advised. If the bulk
milk tests are negative but there are abortion cases, heifer calves of
seropositive dams are tested and removed from the breeding stock if
positive. In herds with positive bulk milk tests, individual testing
of a representative sample of the herd (where there is no evidence of
_N. caninum_ abortion cases) or the whole herd (if over 60 percent of
aborting cows test seropositive) is undertaken to assess the
within-herd seroprevalence. Herd-specific measures are adopted
depending on within-herd seroprevalence and individual management
choices.

2. Switzerland:
Bovine neosporosis is a notifiable disease subject to surveillance.
Although veterinary diagnostic laboratories have an obligation to
report any _N. caninum_ serological or molecular test conducted and
its outcome, there is no national control program. When diagnosis of
_N. caninum_ infection is confirmed in aborted foetuses and
serologically in dams, serological testing of the whole herd is
conducted, and selective breeding of _N. caninum_ seronegative animals
is generally advised.

3. Israel:
No national control programme for bovine neosporosis. The Veterinary
Services recommend serological testing of replacement stock before
purchase. IFAT is routinely carried out although, in aborting animals,
IgM titres are also measured. Given the high seroprevalence in dairy
herds (about 40 percent), vaccination with live _N. caninum_
tachyzoites is currently being investigated as a possible option for
controlling the impact of the disease.

4. UK and Ireland:
The self-regulatory body for cattle health schemes added bovine
neosporosis to the panel of non-statutory diseases of cattle whose
control programs have been standardised to obtain high health
certifications (<https://www.checs.co.uk/diseases/neospora/>). In
member herds, a representative number of cows are sampled and
serologically tested to assess infection at the herd level. In herds
with _N. caninum_-seropositive animals, all female breeding animals
are progressively tested and positive animals removed. In the case of
abortion, the aborting cows and their cohorts are sampled and the
seropositives removed. Added replacement cattle are also tested and
are considered potentially infected until they test negative twice in
proximity of 2 calvings. Biosecurity requirements to prevent
horizontal transmission must also be fulfilled.

References
1. Guido S, Katzer F, Nanjiani I, Milne E & Innes EA. Serology-Based
Diagnostics for the Control of Bovine Neosporosis (Review). Trends in
Parasitology (2016), Vol. 32, No. 2, 131-143.
<http://dx.doi.org/10.1016/j.pt.2015.11.014>
- Mod.AS

HealthMap/ProMED map available at:
Wales, United Kingdom: <http://healthmap.org/promed/p/281>]

[See Also:
Neospora caninum, bovine - UK: (Wales), spread, prevention
http://promedmail.org/post/20180706.5891156
Neospora caninum, canine - USA: (NC) parasite
http://promedmail.org/post/20180618.5862209
2015
----
Neospora caninum, canine: progressive neuron disease, comment
http://promedmail.org/post/20150405.3278517
Neospora caninum, bovine - UK: prevention, control
http://promedmail.org/post/20150402.3268975
2012
----
Neospora caninum, bovine - UK: (England)
http://promedmail.org/post/20120830.1273827
2001
----
Neospora, cattle: significance
http://promedmail.org/post/20010302.0419
Neospora, cattle - USA (Texas) (02)
http://promedmail.org/post/20010227.0384
Neospora, cattle - USA (Texas)
http://promedmail.org/post/20010225.0369]
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