New oil-based foot and mouth disease vaccine effective

Livestock diseases pose the greatest challenge to dairy and beef production in Kenya because they reduce productivity, increase the cost of treatment, and sometimes end up in death. One of these destructive diseases is the foot and mouth disease (FMD). This disease affects cattle, pigs, goats, and sheep and results in the imposition of quarantines that negatively affect trade in animal and animal products from affects areas.

Foot and mouth disease is a contagious viral illness of livestock and other mammals and can potentially cause severe economic losses. Exotic animals reared under intensive production systems, for example zero-grazing, are more susceptible to FMD, making it one of the most economically important disease in dairy production. The disease causes death in young stock, while in adult stock it greatly reduces production. Recovering animals are normally debilitated and weak.

Symptoms

The disease is spread through respiratory and oral routes when a healthy animal breathes in or ingests breath or secretion from an infected animal. Among the clinical signs shown by an infected animal are increased salivation, appearance of blister-like sores on the tongue, lips, mouth cavity, nose, teats, pressure points on the limbs especially in pigs, between toes and hooves, and marked reduction in milk production. The virus can cross to the foetus in pregnant animals, resulting in abortions. In young stock, FMD causes death as the virus affects the heart muscles.

In Kenya, the disease is caused by four viral strains; there are seven viral strains globally. FMD spreads fast irrespective of national borders and is, thus, a trans-boundary disease that calls for regional interventions for its control and subsequent eradication. Disease is spread in endemic areas and tends to follow animal and human movements. Movement controls for animals during outbreaks is one of the disease prevention approaches.

The following are ways through which the virus is spread: New animals carrying the virus in milk, saliva or semen introduced into a naïve herd, contaminated pens, buildings or vehicles used to house and move susceptible animals, contaminated materials such as hay, feed, water, milk or biologics, people wearing contaminated clothes or footwear, or using contaminated equipment, meat or animal products, raw or improperly cooked food infected with the virus and fed to susceptible animals, and aerosol spread of virus from an infected property via air currents.

According to the 2009 animal census Kenya was home to 17.5 million cattle, 17.1 million sheep, 27.7 million goats and 0.4 million pigs. Foot and mouth disease is endemic in Kenya and, therefore, this huge livestock resource can only be protected by vaccination.

Measures taken

The Kenyan Government, through the Kenya Veterinary Vaccines Production Institute (KEVEVAPI), has been producing FMD vaccines in an effort to control the disease. Until early this year farmers have been using a water-based FMD vaccine which, though effective, presented a number of challenges in the field. The old vaccines had a short shelf life and had to be administered three times a year as its immunity lasts for only 3-4 months. This translated to high costs of vaccination and expiry of the vaccines when uptake was low.

To overcome this hurdle the Government, through KEVEVAPI, has produced novel purified oil-based FMD vaccine which has a longer shelf life and confers a longer immunity of up to 12 months. Farmers can now protect their animals against FMD by vaccinating animals over two years old only once a year, with cattle below two years of age getting a booster six months after vaccination. A dose of this new oil-based vaccine costs Sh360. This means that farmers will make a cost saving as compared to when they used the water-based FMD vaccine, which costs Sh645.

The new vaccine will be useful in the progressive control of foot and mouth disease. This will result in increased livestock productivity, household incomes, and reduced cost of vaccination.

Dr Tuimur is the Principal Secretary State Department for Livestock in the Ministry of Agriculture, Livestock, Fisheries