Grazing Cattle

Anthrax was recently reported in humans in western Kenya, specifically Kakamega. This follows other sporadic outbreaks in other parts of the country. This is happening because of low risk perception index among humans that makes this disease to easily cross over from animals to humans.

What is Anthrax?

Anthrax is a zoonotic disease caused by a bacteria called Bacillus anthracis. The disease occurs and is fatal in wild and domestic herbivores like antelope, cattle, camel, sheep and goats. Anthrax can also infect dogs, horses and pigs but in a mild form. But the disease is also zoonotic meaning that it can also affect humanS and this is normally through handling of carcasses that have died of anthrax or consumption of meat from such animals.

Clinical Signs

An animal will show clinical signs for anthrax as quickly as three days or as long as two weeks following an exposure to the causative bacteria. The disease has a peracute, acute and chronic forms. The per acute form is common in cattle and death is observed shortly after movement in-coordination, difficult breathing, trembling, convulsions and collapse.  Fever, excitement are additional clinical signs in acute form. Other signs include subcutenous swellings around the neck, thorax and shoulders.

How is it transmitted?

The infective spores from this bacteria remain viable in soils for many years and are normally formed in conditions of low oxygen as a survival mechanism. From the soil they become a potential source of infection for animals grazing in such areas through ingestion. Flies can also mechanically transmit this disease from one animal to the other this is common in conditions that favour high fly population for example during rainy seasons.  Contamination of animal feeds with Bacillus anthracis is another source of infection for animals further denoting the importance of carcass disposal. This mode of transmission is sustained by dogs, wild carnivores where the carcass is not disposed of properly.

Human Cases

Human cases normally follow bodily contact with carcasses of animals that have died of anthrax. This happens in cases of illegal home slaughters. There are three forms of this disease in humans namely cutaneous, respiratory (inhalational anthrax/woolsorter’s disease) and gastro-intestinal conditions.  Inhalational form is fatal and has a high mortality rate.

Clinical Signs and Lesions in Animals

The characteristic post mort sign is the absence or incomplete rigor mortis. When anthrax is suspected DO NOT open the carcass as this further increases the contamination and spread of the disease. Blood that does not readily clot will ooze from all body openings.

How to Treat, Control and Prevent Anthrax 

Luckily there is an effective and affordable vaccine in the market. Annual vaccination is therefore a cost effective aND preventive measure. When anthrax is reported a quarantine banning livestock movement into and out of the infected zones should be instituted to prevent the spread of the disease. Healthy animals in a herd where the disease has been reported should be treated by a veterinary doctor.

Proper Carcass Disposal

Incineration remains the best and safest way to dispose infected carcasses. The animal should be burnt into ashes. Although burying can be done, it does not rule out future infections from spores from buried carcasses.