Recently, the Nigeria Institute for Trypanosomiasis (and onchocerciasis) Research, NITR, held a conference on trypanosomiasis and onchocerciasis research, zoonotic and public health implications, control and eradication in Nigeria.
Also known as African sleeping sickness, trypanosomiasis is endemic to sub-Saharan Africa. It is caused by protozoan parasites called trypanosomes, which are spread by the bite of the tsetse fly.
Onchocerciasis (otherwise known as river blindness) is a notorious filarial infection caused by the worm, onchocera volvulus. Analysts say it is rather wide spread in parts of sub-Saharan Africa and constitutes the world’s second leading infectious cause of blindness. Although it may not lead to death, the disease causes chronic suffering and severe disability in infected individuals. It is also responsible for serious coetaneous damage in infected individuals with far-reaching psycho-social and socio-economic implications.
At the opening of the conference, the minister of Science and Technology, Professor Ita Ewa said that the ministry is drawing up a five-year strategic plan for research, control and eradication of the diseases. The minister, who was represented by the permanent secretary of the ministry, Mrs. Rabi Jimeta, stated that the five-year strategic plan when approved would serve as a guide not only for NITR but also as a platform for collaboration among stakeholders, ministries and agencies.
The theme of the conference, he said, was “apt and in line with the core objectives of the new National Science, Technology and Innovation, STI, policy towards the achievements of the transformation agenda of President Goodluck Jonathan”. The minister was optimistic that the conference will provide a platform for scientists to present and discuss results of recent research findings on African trypanosomiasis and onchocerciasis so that the menace of these diseases will be totally eradicated in Nigeria in no distant time.
The director general of NITR, Professor Muhammad Mamman in his speech, said that despite the efforts being made, the diseases tend to persist in the country. “Despite several years of extensive efforts on research and development, vector control and host treatment, trypanosomiasis, onchoccerciasis and their respective vectors persist in Nigeria because the conditions that favour their persistence also persist”, he said.
Mamman said that due to the health and socio-economic effects of these diseases, the nation’s goal on achieving food security and self-sufficiency in agriculture, sustainable supply of animal protein and milk will remain unfulfilled, and called for adequate attention to be given on the dangers posed by these diseases. He went on to emphasise that “animal trypanosomiasis (sammore) has remained a permanent disease of our livestock for several decades and causing annually losses of billions of naira due to decreased productivity and death”.
Mamman said that in recent years, the epimiological status of these two diseases and their vectors remained outdated and unless such data becomes available, the severity of their impacts on the nation’s socio-economy, public and animal health would remain elusive. According to him, further availability of such data is critical to the design of strategies to control or eradicate the diseases and their vectors. Thus, there is absolute necessity to, in the near future, conduct a nationwide surveillance on trypanomiasis, tsetse flies, onchocerciasis and black flies.
However, as NITR is trying to effect positive changes, Mamman pointed out that the diseases are not only found in Nigeria, as so many other countries, especially in Africa, still face the challenge. He said that the conference would create avenue for stakeholders to rub minds together. “As you may be aware, both trypanomiasis and onchocerciasis are not limited to Nigeria in their natural occurrence and distribution. Fighting the two diseases is therefore not limited to Nigeria. Indeed, there currently exist the Pan African Tsetse and Trypanosomiasis Eradication campaign, PATTEC, African Programme for Onchocerciasis Control, APOC, etc.
“We convene this meeting for several reasons but mainly to enable stakeholders to become informed and updated on the research that has taken place on the two diseases and their vectors nationwide; compare the level of our research with that currently available globally and rationally identified our gaps and inadequacies a basis to put all necessary measures to upgrade our research levels that shall assist us to effectively achieve the desired capacity to address our domestic problems due to the two diseases; draw a strategic plan to achieve the critical mass of research scientists and technical capability required to successfully implement our strategies with strong likelihood of achieving positive outcomes in the immediate and long terms; establish and strengthen network of research scientists that shall work to render Nigeria free of trypanosomiasis”, he said.
In his paper titled ‘Status and Future Prospects for Trypanosomiasis and Onchocercialisis Research and Control in Nigeria,’ the guest speaker, Professor Moses Iwuala said that the two rank among the most important forms of tropical vector-borne diseases and have been of concern not only to the World Health Organisation, WHO, especially through its TDR programme, but also to the health authorities of many developing countries for some past decades.
With particular reference to African trypanosomiasis, Iwuala said available records indicate that sleeping sickness occurs in 36 sub-Saharan African countries where the primary vector, the tsetse fly (Glossina spp) may be found. People most exposed to tsetse flies and the disease, according to record, are essentially rural populations engaged in agriculture, animal husbandry, fishing and hunting, etc.
The parasite trypanosoma brucie gambiense accounts for other 95 percent of cases of sleeping sickness reported so far. Professor Iwuala hinted that following sustained control efforts over the years, the number of cases hitherto reported dropped to below 10, 000 in 2009, and the trend has been maintained in the past few years with barely 7, 139 new cases reported in 2010.
Nevertheless, proper diagnosis and treatment of the disease, he said, has remained fairly complex. The same is true of meaningful control of the vectors, especially as they require skilled and competent staff.
In consequence, Professor Iwuala posited that “vast expanses of otherwise fertile and arable lands have been abandoned in various countries owing to the severe scourge of the black flies and the disease. So far, an estimated number of over 78 million people globally are literally at risk of onchocerciasis with about half a million people in 35 countries known to be blind. These include an estimate of over 300, 000 persons in 28 countries in Africa, where about 99 per cent of the infected people live.”
The spread of the diseases, he said, are conditioned and influenced by a variety of factors ranging from “geographical and environmental factors, to ecological factors, epidemological and seasonal factors as well as biological parameters as the species and strains of parasites and/or the vectors involved. The population characteristics and behaviour of the human and animal husbandry practices may also count importantly as factors determining or influencing disease spread and sustenance especially in the case of human and animal trypanosomiasis; and to some extent in onchocerciasis”.
Speaking further on the potential research and control options for the future, he said that one of the most attractive options available for tackling the problem of microbial, parasitic and other communicable diseases is that of vaccine development. “The reason is evident because of the target specific nature, and the inbuilt advantages of host immune development and protection. There is also the fact of minimal environmental contamination and other side effects that can otherwise discourage control efforts. Positive reports with respect to vaccine development have been recorded in recent times”, he said.
Closely related option to this, he added, is the molecular biology approach and the employment of sundry biotechnology techniques in dealing with the parasite itself. This approach, he said, has opened up a range of viable options in the control of several parasitic and other communicable diseases, and it holds a great promise for the future, not only for trypanosomiasis and onchocerciasis, but also other forms of tropical diseases of importance. Besides, this approach, he further emphasised, might be useful in dealing with both the parasites and vectors.
Also very promising, the expert said are recent developments in the area of nanotechnology and the active use of bio-informatics in the control of diseases in various countries, regions and geographical zones. This approach he said has proved very useful in dealing with the challenges of malaria, yellow fever and some neglected tropical diseases.
He also added that the use of irradiation techniques and chemosterilisation procedures in dealing with various vector populations have also been proposed for further exploration, as was hitherto the case under the sterile-mate control initiative of the past.
He maintained that further exploration of the principles in dealing particularly with resistant pest and vector populations might yet prove rewarding not only in the control of trypanosomiasis and onchocerciasis, but also in handling the challenges posed by other pests of agricultural and public health importance.
He concluded that effective control of trypanosomiasis and onchocerciasis and other forms of tropical diseases must be based on an “integrated package that addresses not only the elimination of the parasites, but also the vectors, plus proper treatment and protection of the animals”.
The said integrated package, according to him, should also be such as can be cost-effective and subject to proper monitoring and assessment of the control efforts. He said there should also be some well mapped-out short, medium and long term research efforts to back-up available control programmes and guide future initiatives.