BY DR. TONY MONDA
For the past two decades or so, the seasonal resurgence of Theileriosis in Zimbabwe has been cause for concern. Whilst veterinary research and epidemiology studies have improved to address agro-bio-societal changes – chief amongst them is the eradication of agricultural pests and livestock/animal diseases important for both human and animal survival, a practical national livestock disease control programme, engaging veterinary practitioners is yet to be implemented in Zimbabwe.
Animal scientists and veterinary practitioners have the responsibility to protect human health and well-being by ensuring food safety through the prevention and/or controlling animal diseases; preventing emerging infectious zoonoses; protecting environments and ecosystems, as well as assisting in the prevention of possible bio-chemical terrorism and agro-terrorism through contaminated agricultural produce, and thus promote national food security
Veterinary practitioners are also responsible “. . . for advancing treatments and controlling zoonotic and non-zoonotic diseases (such as vaccine-preventable illnesses and chronic diseases), contributing to public health and engaging in medical research” (Pappaioanou, 2004).
Despite the importance of veterinary intervention on animal and human welfare, support for it appears to be isolated and inadequate and not commensurate with its overall effect and societal contribution.
Today in Zimbabwe, the much talked about Theileriosis, also known as January Disease, caused by Theileria parva – a are very small blood-borne parasite called protozoa continues unabated. The infective sporozoite stage of the parasite is transmitted in the saliva of infected ticks as they feed.
On a global scale there are variations in diseases caused by the different species of the parasite, with the most severe being east coast fever, which is endemic in African countries. It has long been considered that tropical and sub-tropical climates tend to favour the survival and transmission of the Theileria.
Different species of Theileria cause different diseases in animals, but the two of most concern in South Africa are corridor disease and turning sickness which results in brain damage.
Corridor Disease, caused by Theileria parva lawrencei protozoa – is also known as buffelsiekte, as it is spread by buffalo. It occurs near wild life environs when buffalo come into contact with domesticated animals. The presence of a single buffalo for a relatively short period may cause a serious outbreak of disease among cattle.
Symptoms of Corridor Disease include fever, combined with depression, listlessness or standing apart, enlarged glands (lymph nodes, especially below the ear and those in front of the shoulder and the knee),
decreased milk production, loss of appetite, watery discharge from eyes, weakness and difficulty in breathing – especially just before death which follows 3-4 days after the first signs of the disease In at least 80% of infected animals.
The disease is acute and progresses very quickly; treatment is usually not possible. The disease is called ‘corridor disease’ because it was first identified in South Africa in the ‘corridor’ between the Hluhluwe and Umfolozi game reserves in KwaZulu-Natal. It currently occurs in Limpopo, Mpumalanga, KZN, Botswana, Mozambique, Angola and Zimbabwe. After Foot-and-Mouth disease, it is the second-most important disease transmitted from buffalo to cattle.
Turning sickness occurs in young cattle. They are infected when bitten by brown ear ticks carrying Theileria Taurotragi protozoa.
The disease can occur wherever the ticks are found and usually results in death within a few days of the symptoms appearing, redness and bleeding in the brain and the covering of the brain may be seen in dead animals. Symptoms include walking in circles – giving the disease its name, staggering, blindness and paralysis.
In its many strains, variants and compounded complications, Theileriosis continues to wreak havoc to livestock throughout susceptible regions in the country this agricultural season (2021-2022), as it has done for the past several seasons, the latest being 400 cattle deaths reported in the Midlands area; however numerous others go unrecorded.
Dr. Tony M. Monda BSc, DVM, is currently conducting Veterinary epidemiology, Agronomy and Food Security and Agro-economic research in Zimbabwe. E-mail: tonym.MONDA@gmail.com
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