FOOD security through the effective control of animal disease is essential, especially the control of ecto-parasites in smallholder rural farming areas of Zimbabwe.
Although semi-arid regions in Zimbabwe are suited for extensive livestock husbandry, that is, cattle and other small ruminants, animal performance in these areas remains subdued owing to numerous interactive factors — key among them being diseases and poor health management.
Livestock, especially cattle, play a crucial role in the livelihood of the population of Zimbabwe where the majority live in rural areas.
Here, crop production is restricted by low and poorly-distributed rains coupled with recurrent droughts; their importance, especially to food security, is even greater.
As I previously mentioned in an earlier article, one of the major health concerns affecting livestock are ecto-parasites, particularly ticks and tick-borne diseases (TBDs).
A disease is defined as any condition that causes the systems of animals not to function properly, and also include bacterial and viral diseases.
Bacterial diseases include abortion, anthrax, (calf) scours, mastitis and tuberculosis.
Abortion, the expulsion of a premature foetus in fifth-to-seventh month of pregnancy, is a zoonotic disease spread through contact.
Anthrax, another zoonotic disease, has a high mortality rate, which is caused by bacterium called bacillus anthracis that produce relatively large spores on contact with oxygen.
A highly infectious and fatal disease of cattle, anthrax causes acute mortality in ruminants and occurs on all the five continents.
The bacteria bacillus anthracis produce extremely potent toxins which are responsible for the ill effects, causing a high mortality rate.
Signs of the illness usually appear within three-to-seven days after the spores are swallowed or inhaled.
Anthrax typically causes an unusual rise in body temperature followed by depression, cardiac distress, staggering and death. Affected animals sometimes die of suffocation, usually within two days, once signs manifest in the animals.
Hoofed animals, such as cattle, deer, goats and sheep, are the main animals affected by this disease.
They usually acquire the disease by swallowing anthrax spores while grazing on pasture contaminated with bacillus anthracis spores.
Inhaling the spores, which are odourless, colourless and tasteless, may also cause infection in animals and people.
There are three types of anthrax which affect skin, lungs and the digestive system.
Generally, outbreaks of this disease occur in areas where animals have previously died of anthrax due to the presence of spores which remain viable for decades.
Large numbers of anthrax spores were released by the Selous Scouts during Zimbabwe’s war of liberation (circa1965-1979) despite the world-wide ban of chemical warfare causing great fatalities among the indigenous population and their cattle.
Blackquarter or blackleg, is a soil-borne infection which generally occurs during the rain season.
It is an acute, infectious and highly fatal bacterial disease of cattle, buffalo, sheep and goats.
Young cattle between six-to-24 months of age, in good body condition, are mostly affected.
Calf scours usually appear in calves under five days of age.
It is a common contaminant in manure and may build up to epidemic levels.
Calf scours is the primary cause of death in calves from two-to-30 days of age.
It is usually caused by bad hygiene, feeding management or both and is known to cause high financial loss to calf producers.
Rotavirus and coronavirus are the causative organisms that contribute to calf scours.
On their own, they usually produce only mild disease signs, but become more severe when combined with stress or other agents.
Mastitis, or inflammation of the mammary gland is a bacterial disease of the cow’s udder.
Here, infection caused by almost 20 different bacteria occurs through the teat canal, mainly due to bad hygiene.
There are two types of mastitis; clinical and sub-clinical mastitis.
Mastitis, is the most common and the costliest disease of dairy cattle in the world.
Although stress and physical injuries may cause inflammation of the gland, infection by invading bacteria or other micro-organisms like fungi, yeasts and possibly viruses is the primary cause of mastitis.
Infections begin when micro-organisms penetrate the teat canal and multiply in the mammary glands.
Pink-eye is an eye infection of cattle due to a specific bacterium that is commonly carried by many normal animals.
A herd outbreak of pink-eye is often precipitated by eye irritation (dust, sunlight, etc).
The infection is readily spread to other animals by flies during summer, the period of greatest exposure.
Tuberculosis – a zoonotic disease caused by mycobacterium bovus — affects all types of cattle.
Clinical signs for tuberculosis include weakness, loss of appetite, weight loss and diarrhoea.
Tuberculosis can also be transmitted through raw milk.
Other respiratory disease in cattle include bovine parainfluenza virus, bovine respiratory syncytial virus, bovine coronavirus, bacterial pneumonia and lungworm.
Viruses are infectious agents that replicate within cells of living host.
Among them are, bovine viral diarrhoea (BVD), blue tongue, rinderpest as well as foot and mouth disease (FMD) that keep recurring needlessly in Zimbabwe
Bovine viral diarrhoea is a common cause of respiratory and reproductive cattle problems.
Signs of acute infection of BVD include fever, lethargy, loss of appetite, ocular discharge, diarrhoea and decreasing milk production.
Infected animals must be culled.
The viral disease blue tongue, spread by insect vectors, is characterised by fever, widespread hemorrhages of oral and nasal tissue, excessive salivation and nasal discharge.
Blue tongue cannot be spread without the presence of insect vectors.
Dr Tony Monda holds a PhD in Art Theory and Philosophy and a DBA (Doctorate in Business Administration) and post-colonial heritage studies. He is a writer, lecturer, musician, art critic, practising artist and corporate image consultant. He is also a specialist art consultant, post-colonial scholar, Zimbabwean socio-economic analyst and researcher.
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