The ongoing struggle in Nigeria to eliminate Human African Trypanosomiasis, commonly known as sleeping sickness, a Neglected Tropical Disease, has been a relentless one, as researchers point to the challenge of effectively controlling and eradicating the tsetse fly (Glossina genus), the disease vector, as a major setback.
Despite extensive mass treatment efforts and disease awareness campaigns, the prevalence and impact of HAT on the population have persisted at levels below 10 per cent. Experts have highlighted various factors such as rural-urban migration, the persistent presence of the disease in animals, and the influence of climate change as drivers that contribute to the resilience of the disease-carrying vector.
Nigeria grapples with two forms of trypanosomiasis: the Human African trypanosomiasis or Sleeping sickness affecting humans and the Animal African trypanosomiasis, known as Nagana.
According to the World Health Organisation, HAT is a parasitic disease transmitted by protozoans of the genus Trypanosoma through the bites of tsetse flies infected with the parasite. The disease, famously known for causing disruptions in the sleep cycle of infected individuals, poses a significant health threat in 36 sub-Saharan African countries where tsetse flies are present.
These flies act as carriers of the disease, predominantly affecting rural populations who rely on farming, fishing, and hunting for sustenance. Both human and animal forms of trypanosomiasis fall under the category of neglected tropical diseases, carrying severe health, social, and economic burdens.
The complex epidemiology of Neglected Tropical Diseases, affecting over 1 billion individuals globally, is intricately linked to environmental conditions, complicating efforts for their effective public health management.
In 2021, the World Health Organization (WHO) created a roadmap to eliminate Neglected Tropical Diseases (NTDs) by 2030. So far, the WHO has confirmed that seven countries – Cote d’Ivoire, Togo, Benin Republic, Equatorial Guinea, Uganda, Ghana, and Chad – have successfully eliminated NTDs as a public health concern.
Although Nigeria has not reported any new cases of Trypanosomiasis, a review of research conducted between 1993 and 2021 found that the country still faces a significant burden from sleeping sickness and Nagana, with prevalence rates of 3.6% and 27.3%, respectively.
Neglected Tropical Diseases are a group of infectious diseases that thrive in tropical and subtropical regions, and have long been overlooked due to a lack of attention and resources dedicated to their prevention and control.
The WHO plays a crucial role in guiding the identification and management of these diseases.
It said, “The neglected tropical diseases include onchocerciasis, schistosomiasis, lymphatic filariasis, soil-transmitted helminth infections and trachoma. Also among them are dengue fever, leptospirosis, trypanosomiasis, leishmaniasis, Buruli ulcer, leprosy and snake-bite envenoming,”
The publication further noted that over 170,000 people die of these diseases annually – fewer than malaria with 627,000 deaths in 2020.
However, the greatest danger associated with these NTDs is that they can cause “disfigurement, stigmatisation, malnutrition and cognition problems, leading to a range of social, economic and psychological burdens for those affected.
“Nigeria carries a particularly heavy burden. A quarter of the people affected by neglected tropical diseases in Africa live in Nigeria. An estimated 100 million people in the country are at risk for at least one of the diseases and there are several million cases of people being infected with more than one of them.”
Professor Chinyere Ukaga, a parasitology expert, explained that while the World Health Organization (WHO) has reported zero new cases of sleeping sickness in Nigeria, this does not necessarily mean that there are no cases present in the country.
However, she acknowledged that Nigeria is making significant strides towards eliminating the disease.
“The WHO has set criteria, as well as guidelines, which must be met before a country is declared to have eliminated any NTD including sleeping sickness.
“However, considering the report by Odebunmi et al. 2024 with a sleeping sickness prevalence of 3.6 per cent and 27.3 per cent prevalence of Nagana in 2021, Nigeria is not free yet from this disease despite the zero new cases reported by the WHO.
“The disease in humans and animals, especially cattle is caused by the same parasite and transmitted through the bite of the same vector Tsetse fly (Glossina spp.).
“The implication is that as long as the animals are not free of the parasite, humans will not be free. Animals serve as a reservoir for the trypanosome parasite that causes trypanosomiasis and at any given opportunity, these parasites are transmitted to humans by the Tsetse flies,” Ukaga highlighted.
According to Professor Chinyere Ukaga, a Public Health Parasitologist, Nigeria’s efforts to eradicate sleeping sickness are hindered by the challenges in controlling the disease-carrying vectors, specifically the tsetse fly.
She attributed this to factors such as climate change and the migration of vectors from neighboring countries, which contribute to their proliferation in Nigeria.
Ukaga, who is currently the Director of Academic Planning at the Wigwe University, Rivers State, warned, “There will be a rise in the disease if nothing is done but something is being done.
“There are ongoing efforts by different sections including nongovernmental organisations working on NTDs and the Federal Ministry of Health, especially the Directorate of NTDs towards the elimination of this disease. There are also Research Institutions dedicated to the control of this disease in the country.”
Professor Chinyere Ukaga warned that anyone bitten by an infected tsetse fly is at risk of contracting sleeping sickness. She emphasized that pregnant women who are bitten can pass the disease to their unborn babies, as the parasite can penetrate the placenta.
Additionally, laboratory accidents involving contaminated needles can also lead to infection. The expert listed early symptoms of sleeping sickness in humans, including recurring fever, headache, swollen lymph nodes, joint pain, and itching.
“At the second stage, if untreated, the parasites cross the blood-brain barrier into the central nervous system causing the meningo-encephalitic (inflammation of the meninges, the protective membranes covering the brain and the spinal cord) and the brain itself.
“Generally, this is when more obvious signs and symptoms of sleeping sickness appear: behaviour changes, confusion, sensory disturbances and poor coordination. Sleep cycle disturbance, which gives the disease its name, is a prominent feature.
“Without treatment, this disease is usually fatal, resulting in the death of the affected persons. Although, rare cases of self-cure have been reported by the WHO,” she mentioned.
The parasitologist stated that climate change contributes to the escalation of especially, vector-borne NTDs, including sleeping sickness.
The don stated, “Studies have shown that climate change promotes a shift in these vectors as warmer temperatures encourage the geographical spread of the vectors while more standing waters as in floods also promote increased breeding areas for the vectors.”
She emphasised the need for increased awareness of the diseases, especially among cattle breeders and herdsmen to ensure treatment of their cattle to prevent animal-to-human transmission.
“The cattle breeders including herdsmen and everyone living in tsetse fly biting zones should be encouraged to always put on protective clothing and use insecticides on the exposed parts of their bodies while moving with their cattle and working in the farms or fishing etc.
“There should be more efforts targeted at the elimination of the vectors. There is a need to educate everyone living in the at-risk areas on the early signs of the diseases, which can be treated effectively.
Treatment becomes very difficult when the parasite crosses the blood-brain barrier. Early reports of cases should be encouraged. For the other NTDs, awareness and early detection is key to the effective control of whatever NTD is being considered,” Ukaga stated.
Professor Patricia Lar, a Medical Microbiology expert at the University of Jos, emphasized that although the prevalence of sleeping sickness is relatively low, below 10%, there is still a pressing need for heightened awareness and education on preventing human contact with the disease-carrying vectors, such as tsetse flies, to achieve complete eradication of the disease.
“Also, what I call the mass treatment campaigns with anti-parasitic agents, over the years has brought it below 10 per cent in the population and has generally been significantly reduced in Nigeria.
“Efforts over the years have gone on in terms of knowledge of the life cycle of the vectors that transmit these diseases and there have been improvements in human contact with the environment where these flies breed.”
Professor Patricia Lar explained that while Neglected Tropical Diseases (NTDs) are largely confined to rural and underdeveloped areas, efforts are underway to reduce their incidence, prevalence, and burden.
She attributed the decline in NTDs to rural-urban migration, although it is not well-documented.
When questioned about Nigeria’s progress in eliminating sleeping sickness, compared to neighboring countries that have achieved this feat, Lar cited the country’s large population, both in urban and rural areas, as a significant challenge to overcome.
When asked why Nigeria has not yet eradicated sleeping sickness despite neighbouring countries achieving this milestone, Lar mentioned, “I would say as much as a lot is going on, we still have a massive population, whether in the urban or rural areas.
“Nigeria as a nation has an expansive population, that on its own has had an impact on the allocation of resources, the general control, as much as the massive corruption that has also impacted the availability of resources down the ladder, down the cadre in society. I think all of this contributes to Nigeria not being able to achieve 100 per cent eradication.”
Professor Patricia Lar stressed the importance of ongoing awareness and treatment campaigns in communities vulnerable to sleeping sickness and other Neglected Tropical Diseases (NTDs).
She highlighted the need for sustained efforts to identify and eliminate the disease-carrying vectors, such as tsetse flies, in areas where they thrive, in order to achieve complete eradication of these diseases.
“Also, there is the need for strategic identification in environments with thick forests and areas that are still conducive for the breeding of the vectors that transmit this disease. The campaigns have to be sustained.
“The sustainable development goals are rolled out to ensure total health and well-being of populations and every country, including Nigeria, has signed up to participate. Whether we like it or not, the media should get involved in creating awareness among populations.
“The government has to also sustain funding to the health sector so that it increases continuous surveillance to be able to achieve this minimal level.
The level that can get Nigeria to be certified clean is when we have maybe less than 10 per cent or 5 per cent reports of the incidents or the burden in a particular year.
So until we get to that level, we will continue to have sporadic cases and in some cases, we might become a challenge to other nations around,” the Medical Microbiologist highlighted.
In conclusion, Professor Patricia Lar urged for comprehensive education of Nigerians utilizing available resources, ensuring access to sustained treatment options, and emphasizing the crucial need for prompt detection and response to outbreaks to effectively control and prevent the spread of sleeping sickness and its vectors.
