Theburden of neglected tropical diseases on humans and animals

Thursday March 8 2018

By Lominda Afedraru

It is a fact that most health experts will talk about neglected tropical diseases being a burden to human beings forgetting it affects animals as well.

These diseases can be transmitted from animals to human beings meaning that interventions to curb them must be applied to both animals and people to avoid a rotational circle of infection.

Scientists refer to them as zoonotic diseases which are transmitted from animals to humans and vice versa.

Veterinary scientists with expertise in the subject explained about the dangers of these diseases and possible solutions during the 8TH conference organized by Kenya Medical Research Institute (KEMRI) in Nairobi Kenya with most of them urging governments in East Africa to improve on animal health in order to reduce on neglected zoonotic health disease infection in the region.

Dr Robert Ndugu from Kemri Kisumu explaining about the burden of the diseases in East Africa noted that the most common shared are Helminths.

Incidences of Helminths


These are worms which have overwhelmed humans since before the era of the earliest records in history. They include hookworms, tapeworms, roundworms, liver flukes which cause Bilharzia also known as snail fever thereby destroying human bladder and nagana which causes sleeping sickness.

Dr Ndungu explains that the eggs of intestinal helminths can be found in the desiccated feces of humans and animals. 

Scientists categorise these helminths into two major categories namely the nematodes  known as roundworms which are soil transmitted and the filarial worms that cause lymphatic filariasis spread by black flies which feed on blood and onchocerciasis (river blindness).

 Whereas platyhelminths known as flatworms include the flukes also known as trematodes such as the schistosomes and the tape worms such as the pork tapeworm that causes cysticercosis.

 Others are diseases transmitted to humans by animals such as dogs especially for the case of rabies.

 Dr Ndungu notes that any dog and cat scratch leads to spread of rabies which can cause death after a year or so.

 There is echinococcosis parasitic disease caused by tapeworms and it is transmitted by dogs and pets to human being and other livestock such as sheep, pigs and cattle. It causes swelling in the animal stomach thereby disorganizing the spline. This leads to poor quality beef and milk and if consumed by humans they end up being victims of the disease.

 Another zoonotic disease associated with cats is Toxoplasmosis an infection caused by a parasite called Toxoplasma gondii. It is found in cat feces and undercooked meat, especially lamb and pork.

It can also be transmitted through contaminated water. The infection can cause swellings to form in your body, usually in the brain and muscles, including the heart.

Dr Adele Njunguna who conducted studies about the prevalence of Toxoplasma Gondi in Thika district explains that she discovered that human beings do not mind of cleaning cat feces and so it is very easy to contract the disease.  People living with HIV/Aids are prone to it and it causes abortion in pregnant mothers. It also affects the human eye causing tears.

Chicken which is reared at home feed on the cat feces and human beings can get it from chicken beef.

Dr Hellen Koka who carried a study amongst Kenya’s pastoral communities in Western Kenya about the dangers of tick bone diseases to animals and humans explains that most tick bone diseases in animals end up being contracted by human beings an example being Q fever which is widespread disease caused by the bacteria called Coxiella burnetii, which is able to infect mammals, birds, reptiles and arthropods. It causes a mild disease in ruminants, but can cause abortions and still births in cattle, sheep and goats.

To her ticks globally transmit the widest diversity of pathogens in humans and domesticated animals and they form the largest emerging zoonotic diseases. All tick species have the same bacterial infection.

Neglected human- animal diseases, the case in Uganda

Similar to many other developing countries, Uganda is affected by a high burden of neglected diseases.

The director Mbarara Zonal Agricultural Research and Development Institute (MbZARDI) Dr Halid Kirunda categorizes them as neglected diseases but with immediate government attention in case there is an outbreak.

They include Bovine Tuberclosis a disease caused by bacteria called M. bovis which affects mammals in general causing a general state of illness, coughing, emaciation, exhaustion, weakness and pneumonia, Lymph nodes and eventual death.

Others are brucellosis, Ebola, Marburg, Rift valley fever, Rabies, Polio which affects gorillas and Antrax which is the most deadly killing both animals and human beings within 48 hours.

When Antrax is detected in animals, human beings are barred from consuming meat from infected animals. Appropriate cooking is recommended. In case of early detection heavy Pen Insulin doze can be administered to rescue the animal.

According to Dr Kirunda, if anthrax infects animals and human beings, it can be blown by wind from spores of the skin and other animals and humans will inhale it so easily.

He notes that the common neglected diseases for Uganda’s case are Taenia solium and Taenia Bovis infection which is an intestinal infection with adult tapeworms harbored by humans and disposed through feces.

Animals such as cattle, pigs, Buffalos and sheep will consume the eggs and hatch them into larva which is extended in beef, pork and mutton and further consumed by humans.

Askaris which is transmitted by dogs is also common especially in growing children who tend to play in areas where the dogs have defecated.

Initiatives to control spread of neglected diseases in humans and animals

Most veterinary experts’ advice animals to be treated and vaccinated to avoid spread of these diseases. Limit interaction between humans and animals.

In the case of Dr Kiriunda and team in the agriculture sector, they map areas were the incidence is on the increase and carry out massive immunization exercises particularly for cattle which are not pregnant.

They advise call for deworming in  animals and humans using drugs such as levamisole, Albendazole, Fenbendazole and Mebendazole which can be administered to both humans and animals.

Ten years ago, the incidence of these diseases was on the increase in Eastern and Northern cattle corridors but reducing in Western Uganda due to appropriate farm practices but now it is reducing in all regions due the awareness and sensitization exercise conducted in communities keeping animals.

According to the health experts in Kenya, all these diseases have vaccines therefore it is important to vaccinate the animal against them to curb the level of transmission to humans.

They advise governments to administer animal - human integrated health initiatives and it is important to vaccinate the animals before they get infected with disease because this will help in creating immunity and prevention.

In Kenya, veterinary doctors recommended ministry of health to strengthen surveillance in zoonotic disease especially in communities who are keeping animals.  There are initiates of screening of livestock by spraying them with Acaricides.

Giving the statics quoting the World Health Organization (WHO) the experts revealed that neglected tropical diseases affect almost 1,000,000,000 people in 149 countries.

Most are small family farmers living in the least-developed countries where health systems are inadequate and climate conditions are favourable to infectious and parasitic diseases.

These diseases hinder socio-economic development, maintain poverty, and impede the achievement of UN sustainable development goals at all levels.

Economic analysis has shown that their control, elimination, or eradication would lead to net economic benefits. Rapid progress can be achieved when there are organized health systems, whether public, private, are in place to provide diagnostic methods and facilities, treatments, and vaccines.

Countries are expected to work in private - public partnership

It is stated that the Global Alliance for Livestock Veterinary Medicines now target major livestock diseases impacting smallholder families by connecting academia, public research institutes, and the pharmaceutical sector since the zoonotic diseases have been labeled  as neglected.

The figure indicates that about 60 million in Africa are suffering from sleeping sickness although the number has reduced due to massive surveillance exercise by governments in Africa. The road map is to eliminate it by 2030.