Friday, July 6, 2018

PRO/AH/EDR> Neospora caninum, bovine - UK: (Wales), spread, prevention

NEOSPORA CANINUM, BOVINE - UK: (WALES), SPREAD, PREVENTION
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Date: Thu 5 Jul 2018
Source: AgriLand [edited]
<https://www.agriland.co.uk/farming-news/dog-walking-blamed-for-rise-in-abortion-causing-disease-in-welsh-livestock/>


Concerns over increasing reports of _Neospora_ outbreaks in cattle
have been highlighted at the meeting of the National Access Forum for
Wales held in Welshpool on Tuesday [3 Jul 2018]. _Neospora_ does not
harm dogs, but dogs can carry the disease, which often goes
undetected. The disease does, however, cause harm to cattle and sheep,
and it can result in the abortion of unborn young.

NFU Cymru Rural Affairs Board chairman, Hedd Pugh, said: "In recent
months, NFU Cymru has received increasing reports of outbreaks of
_Neospora_ in cattle. These are coming from all areas in Wales. The
disease is found in dog faeces, which can contaminate the animals'
grazing pasture. That is why it's important that dog owners always
pick up after their dogs."

Dogs owners are also encouraged to keep their dogs away from animal
food and water troughs, as the disease can also be spread that way.
Pugh added: "The impacts of _Neospora_ can result in significant costs
and distress for farmers. We hope, through highlighting this disease
and its impacts to the 40 or so organisations represented on the
National Access Forum, we can raise awareness of this issue to access
user groups and promote the 'bag it and bin it' message to dog
owners." NFU Cymru has signs to remind dog owners to keep their dogs
on a lead around livestock and to pick up after their dog.

[Byline: Rachel Martin]

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Communicated by:
ProMED-mail
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[_Neospora caninum_ is a protozoan parasite of animals. Since its 1st
recognition in dogs in 1984 and the description of the new genus and
species _N. caninum_ (Apicomplexa: Eimeriina: Sarcocystidae) in 1988,
neosporosis has been detected in various species of livestock,
including cattle, sheep, goats, horses and deer. Neosporosis is one of
the most frequently diagnosed causes of abortion in dairy cattle
worldwide. Furthermore, _N. caninum_ infections in dairy cows may also
be associated with premature culling and decreased milk production.

In general, _N. caninum_ is similar in structure and life cycle to
_Toxoplasma gondii_, with 2 important differences: (i) neosporosis is
primarily a disease of cattle; dogs and related canids are the
definitive hosts of _N. caninum_, whereas (ii) toxoplasmosis is
primarily a disease of humans, sheep and goats; felids are the only
definitive hosts of _T. gondii_.

Although antibodies to _N. caninum_ have been reported in human serum,
the parasite itself has not been detected in human tissues. Thus, the
zoonotic potential is uncertain.

Several approaches have been used to control neosporosis in cattle
herds. These include improving farm biosecurity, test and cull
programs, test and exclude from breeding, and artificially
inseminating with beef semen. Biosecurity may prove beneficial to
avoid introducing the parasite into a closed herd not already infected
with _Neospora_.

Farm management practices to reduce _N. caninum_ infection can
include:
(i) minimizing fecal contamination of cattle feed or water by canids;
(ii) prompt removal of aborted bovine fetuses and fetal membranes;
and
(iii) limiting the introduction of infected cattle into the herd and
culling infected animals.

If using the test and cull method of control, every animal must be
serologically tested, and those that test positive must be removed
from the herd. Test-negative animals should be periodically retested
because titers tend to wax and wane, and there is a possibility of
horizontal transmission resulting in new infections. This approach can
be devastating depending on how many in the herd test positive.
Notwithstanding the risk of horizontal transmission, a more economic
approach would be to test each animal and exclude the daughters of
seropositive cows from the replacement pool. If a cow is valuable,
there is always the opportunity to preserve the genetics by embryo
transfer into a seronegative dam.

It is possible to reduce the risk of _Neospora_ abortions in dairy
cattle by inseminating seropositive dams with beef breed semen. This
is effective because crossbreed pregnancies have a more robust
placentation with higher levels of peripartum pregnancy-associated
glycoprotein, which may have a protective value. Beef breeds in
general and the Limousin breed in particular are more resistant to
_Neospora_ infection than are dairy breeds. Beef cow-calf herds that
manage their cows on range for summer grazing have lower
seroprevalence than those that do not, while increased seroprevalence
is associated with higher winter stocking density.

These control methods might not be economically or practically
feasible on dairies or beef cattle operations. Buying replacements
originating from seronegative herds can mitigate the risk of
introducing infected replacements into a negative herd. General
management efforts to reduce stress from concurrent disease,
environmental and social stress, and providing an adequate wholesome
ration may reduce immunosuppression and hence abortion rates.

There is accumulating evidence that some cows infected with _N.
caninum_ can develop a degree of protective immunity against abortion
and/or congenital transmission, indicating that immunoprophylaxis to
prevent abortion or congenital transmission is a feasible goal. A
commercial vaccine is not currently available. In the future, vaccine
development is likely to depend on identification of specific
_Neospora_ genes that may enable the production of genetically
engineered vaccines.

The above information on control/prevention of _N. caninum_ is derived
from the (2015) review by C. T. Estill and C. M. Scully, which also
includes updated information on the epidemiology, lifecycle,
pathogenesis, diagnosis and clinical signs of the disease; see at
<http://media.johnwiley.com.au/product_data/excerpt/34/11184708/1118470834-58.pdf>.
- Mod.AS

HealthMap/ProMED-mail map: <http://healthmap.org/promed/p/281>.]

[See Also:
Neospora caninum, canine - USA: (NC) parasite
http://promedmail.org/post/20180618.5862209
2015
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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]
.................................................sb/arn/rd/jh
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