by Tapuwa Mashangwa

The effects of Covid-19 lockdowns have seen agricultural markets become unstable and at high risk, especially considering how inter-country and intra-country movement has been restricted intermittently, depending on the severity of cases and the control measures a country applies. All agricultural production systems have been affected one way or the other, and cattle production has not been left out, as some diseases have not ceased to affect the production and marketing of meat products.

Diseases common in cattle include bluetongue, botulism, bovine tuberculosis, bovine viral diarrhoea (BVD), brucellosis, Johne’s disease, psoroptic mange, schmallenberg virus, transmissible spongiform encephalopathies, as well as foot and mouth disease (FMD).

In Africa, where cattle ownership and intensive cattle farming production systems exist, FMD has been affecting farmers. Its control is important to promote countries to have access to lucrative national, regional, and foreign meat markets.

FMD is a severe and highly contagious viral disease that has various serotypes. In the case of FMD, a serotype or serovar is a distinct variation within a species of virus or among immune cells of different creatures. There are seven different FMD serotypes that circulate within regional viral pools with periodic incursions into virus-free developed countries.
According to the FMD April-June 2021 Quarterly Report, serotypes prevalent in North Africa (Algeria, Egypt, Libya, Morocco, Tunisia) are A, O and SAT 2.

In Eastern Africa (Burundi, Comoros, Djibouti, Eritrea, Ethiopia, Kenya, Rwanda, Somalia, South Sudan, Sudan, Uganda, United Republic of Tanzania, Yemen), the serotypes are O, A, SAT 1, SAT 2, and SAT 3. For West/Central Africa (Benin, Burkina Faso, Cabo Verde, Cameroon, Central African Republic, Chad, Congo, Côte d’Ivoire, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Mali, Mauritania, Niger, Nigeria, Sao Tome and Principe, Senegal, Sierra Leone, Togo), prevalent serotypes are O, A, SAT 1, and SAT 2. Lastly, in Southern Africa (Angola, Botswana, Malawi, Mozambique, Namibia, South Africa, Zambia, Zimbabwe), serotypes present are SAT 1, SAT 2 and SAT 3 (O, A).

An FMD endemic causes indirect losses for farmers that include:

• Reduced milk production that affects both the humans and calves that depend on it (this can account for 33 percent of losses in endemic settings)
• Reduced livestock growth
• Mortality in young stock, typically reported being between 2 and 5 percent
• Loss of traction power where draught animals are used (if this occurs during harvest the effects can be particularly severe)
• Abortion, which has financial implications due to the high cost of a single abortion that means the farmer will have to pay to keep the cow without it producing anything for another year or more, or cull the animal.

FMD causes problems with fertility. The most obvious is the abortion losses explained above, but there are longer-lasting impacts of this loss of both foetus and a reduced probability of conception. These both translate into the need to have a greater proportion of breeding animals in a population implying that for every kilo of meat or milk produced, there is an additional fixed cost to cover more breeding stock.

The cost of control measures carried out by the state veterinary services, such as vaccination, outbreak control and sometimes culling and compensation are borne by the taxpayer.

Market losses include:

• Limited livestock trade
• FMD-affected farmers receive lower prices for their stock;
• Individuals wishing to purchase animals from FMD-free herds face a restricted supply, and
• Countries infected with FMD cannot trade live animals with FMD free countries

FMD is the most infectious human or animal disease agent known. An infected cow has been estimated to be able to infect over 70 other cattle in a susceptible herd, which allows the disease to spread with great speed.

The importance of trade, both legal and illegal, in the spread of the disease, implies that any FMD control strategy must have policies and actions to limit risks of FMD spread — from an outbreak or the introduction to and from neighbouring countries and trading partners.

The cost of preventing an outbreak of FMD is lower than the cost of managing an outbreak afterwards. Vaccine efficacy is influenced by vaccine potency, antigenic match, and vaccination regime. Therefore, it is possible that a less than perfect antigenic match of a particular antigen may be compensated by using a high potency vaccine and by administering more than one vaccine dose at suitable intervals.

Thus, a vaccine with a weak antigenic match to a field isolate, as determined by serology, may nevertheless afford some protection if it is sufficiently potent and is administered under a regime to maximise host antibody responses.

Some national FMD vaccination programmes vaccinate all bovines three times a year and all sheep and goats once a year. The best way to contain FMD would be the collaborative effort of governments, non-government organisations, livestock and veterinary regulatory bodies, and participants in the private sector to ensure that resources are available to combat and control it.