preventative vaccination programs are considered to
control the secondary bacterial agents it is important
to determine if they are in fact pathogenic strains,
which could then be considered for use in autogenous
vaccines. Autogenous vaccines provide little benefit
if constructed from low pathogenic or opportunistic
strains.
Control Measures
There are currently no licensed therapeutic agents in
South Africa for the treatment of cryptosporidiosis.
Halofuginone is currently the only known
cryptosporidiostatic agent available but can only
be imported on a section 21 permit. Treatment
of clinical cases is largely supportive and should
include electrolyte fluid therapy and treatment of
secondary complicating bacterial infections if present
(consideration of autogenous vaccines with pathogenic
strains). Ensure affected animals have continued
access to a milk supply. Maintaining energy levels and
body weight is important in successful therapeutic
outcomes.
Reducing the number of oocysts ingested reduces
the severity of infections and allows for immunity to
develop. Therefore, disinfection of water supplies
is an important mana gement tool in the control
of Cryptosporidium outbreaks.
Unfortunately,
chlorination of water supplies is ineffective in
destroying Cryptosporidium, but does have efficacy
against protozoa including Giardia and bacteria (E. coli,
Salmonella, Shigella, Campylobacter). Boiling water
supplies with a rolling boil of at least two minutes has
extremely high efficacy in destroying Cryptosporidium
oocysts, as well as Giardia and bacteria (E. coli,
Salmonella, Shigella, Campylobacter).
However,
boiling of water supplies for wildlife consumption
poses practical problems.
In circumstances where boiling water supplies is not
feasible the most effective pathogen reduction method
in drinking water is a combination of disinfection with
Chlorine Dioxide and Filtration with a reverse osmosis /
absolute <1 micron filter. Chlorine dioxide disinfection
alone or filtration alone have low efficacy against
Cryptosporidium, but when used in combination
these combined procedures are highly effective at
eliminating Cryptosporidium oocysts from water
supplies. Unfortunately, reverse osmosis results in a
high level of water wastage.
Environmental control
•
•
Ensure frequent rotation of calving / lambing
camps in breeding facilities, so that animals are
born in a clean environment.
Ensure adequate colostrum intake at an early age.
Human cryptosporidiosis.
Cryptosporidiosis is one of the most common
waterborne diseases of man and is encountered
worldwide. It affects the distal small intestine
(predominantly) and can affect the respiratory tract
of both immunocompetent (normal functioning
immune system) as well as an immunocompromised
(HIV, autoimmune disorders) individuals. The
main species causing clinical disease in man are
Cryptosporidium parvum and Cryptosporidium
hominis. Cryptosporidium canis, Cryptosporidium
felis, Cryptosporidium ubiquitim and Cryptosporidium
muris have also been associated with disease in
humans. Cattle, sheep and goats remain the most
important zoonotic reservoirs of infection for man.
The identification of Cryptosporidium parvum and
Cryptosporidium ubiquitim in African wildlife suggests
that they made too serve as reservoirs for human
infection.
Further Reading
1.
2.
3.
4.
5.
6.
7.
Centre’s for Disease Control and Prevention. Atlanta,
United States of America. https://www.cdc.gov/
Merck Veterinary Manual. 2014. Overview of
Cryptosporidiosis. http://www.merckvetmanual.
com/mvm/digestive_system/cryptosporidiosis
Nada, A S. 2013. An epidemiological study of crypto-
sporidiosis at the wildlife/livestock/human interface
in Mpumalanga province of South Africa. Thesis (PhD)
University of Pretoria. http//hdl.handle.net/2263/32979.
Stewart C G and Penzhorn B L. 2004. Cryptosporidi-
osis. In: Infectious Diseases of Livestock, 2nd edn. Coetzer
and Tustin (eds). Oxford University Press, Cape Town.
Richter B, Nedorost N, Madener A & Weissenbock H. 2011.
Journal of Veterinary Diagnostic Investigation; 23:430-435.
Uzal F A, Plattner B L and Hostetter JM. 2016. Ali-
mentary System. In: Jubb & Kennedy. Pathology of
Domestic Animals 6th edn. Elsevier, St Louis.
Wikipedia. 2018. Cryptosporidiosis. http//
en.wikipedia.org/wiki/Cryptosporidiosis
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