• Marianne Comparet

Pr. Louis-Albert Tchuem Tchuenté University of Yaoundé, Cameroon


Pr. Louis-Albert Tchuem Tchuenté

University of Yaoundé, Centre for Schistosomiasis & Parasitology

Cameroon

Interview by Kamran Rafiq (ISNTD) April 2016

Pr. Louis-Albert Tchuem Tchuenté is Professor of Parasitology at the University of Yaoundé, director & founder of Cameroon’s Centre for Schistosomiasis & Parasitology and Coordinator of the National Programme for the Control of Schistosomiasis and Intestinal Helminthiasis in Cameroon. With 30 years of experience in numerous aspects of management, research and control of schistosomiasis, soil-transmitted helminthiasis and other neglected tropical diseases (NTDs), Pr. Tchuenté speaks here about the main strategies and successes in the control of NTDs, building high political commitments, as well as the challenges remaining ahead for the NTD community.

What have been some of the main public health challenges in Cameroon in recent times and what have been the strategies put in place to address these?

One of the main public health challenges in Cameroon in recent times have been the control of neglected tropical diseases (NTDs). These diseases affect the lives of millions of impoverished populations, and the priority NTDs in Cameroon are schistosomiasis, soil-transmitted helminthiasis, onchocerciasis, lymphatic filariasis, trachoma, Guinea worm, human African trypanosomiasis, Buruli ulcer, leprosy, leishmaniasis and yaws. These diseases are widely distributed and co-endemic in many parts of the country. To overcome these diseases, six specific control programmes have been created between 1998 and 2010. In 2012, a national Master Plan 2012-2016 for the control/elimination of NTDs and the strategies are centered around three drug distribution channels: (i) school-based deworming for schistosomiasis and STH; (ii) community-based interventions for onchocerciasis, LF and trachoma; and (iii) vaccination campaign for the deworming of pre-school aged children (< 5 years).

There have been tremendous efforts across Cameroon but also a number of African countries to comprehensively map Neglected Tropical Diseases. How successful has mapping been in Cameroon and has this translated in more targeted research and control programmes? What have been some of the main chal-lenges nationally as well as regionally in coordinating mapping efforts?

Knowing the distribution of a disease is a prerequisite to properly defining the areas and strategies for control interventions. Cameroon has completed the mapping of the five NTDs targeted by preventive chemotherapy (schistosomiasis, STH, onchocerciasis, LF, trachoma) by 2012, and this was a great achievement and a crucial step to scale- up interventions in all areas of need of mass drug administration in order to achieve targets for control and elimination. The mapping status is very different between health districts in Cameroon and between African countries. Several challenges arose in coordinating efforts within the country and across the continent. These include: coordination of partners and resources for mapping (there are several partners supporting mapping activities in different countries and each partner has an individual vision, interest and mapping approach); harmonisation of tools and method/protocol; and insufficient government leadership (in some countries).

You are extremely active in terms of research on polyparasitism and coinfection. What have been your main findings looking at Cameroon and what implications does this have for control strategies. Is there, globally, a sufficient understanding of coinfection & comorbidity when it comes to NTDs?

My work showed that polyparasitism is frequent in many parts of Cameroon where most children are co-infected by at least two species of parasite. It is likely that people harbouring multiple species infections are subject to heavy infections and will have exacerbated morbidity. Knowing the type of co-infections is essential to developing adequate drug co-administrations. Interestingly, my work demonstrated that interspecific interactions in schistosomes have significant impacts on parasite epidemiology, species location in humans, genetic heterogeneity, transmission dynamics of schistosomiasis and control strategies. My work on human schistosome interactions showed that the presence of Schistosoma haematobium or S. mansoni prevents that of S. intercalatum through interspecific competition processes, and suggested that S. intercalatum was an endangered species in Cameroon.

In your opinion, what are some of the most urgent research priorities for the control of NTDs or schistosomiasis in particular?

Taking into account the different components of NTD transmission – and schistosomiasis in particular – and the control/elimination interventions and challenges, the research priorities to optimize control strategies can be grouped in 5 major core themes:

(1) Intervention

  • Optimize treatment/control strategies according to different transmission dynamics.

  • Reaching unenrolled and pre- school-age children, and high-risk adults with preventive chemotherapy.

  • Monitor drug efficacy and potential drug resistance.

  • Environmental and Snail control.

  • Development of new drugs, and alternative drugs to Praziquantel in particular.

(2) Epidemiology and Surveillance

  • Better diagnostic tools (improved sensitivity and specificity) for monitoring and evaluation in low endemic areas and elimination settings.

  • Development of rapid diagnostic tests for Schistosomiasis.

  • Standardize and validate methodologies and protocols for TAS (Transmission Assessment Surveys) for Schistosomiasis.

  • Development of surveillance-response system for Schistosomiasis control/elimination (Early warning system for surveillance).

(3) Environment and Social Ecology

  • Impact of mixed-infections and co-infections (HIV, STH, malaria, etc.).

  • Social and environmental factors.

  • Snail distribution and dynamics.

  • Water and sanitation interventions.

  • Impact of environmental changes on NTD transmission.

  • Role and impact of animals reservoirs.

(4) Data and Modelling

  • Use of electronic data tools for reporting from the field and feed-back.

  • Develop mathematical models to predict prevalence and intensities curves during preventive chemotherapy implementation in relation to transmission dynamics.

  • More data and research on Female Genital Schistosomiasis.

  • Research on Schistosomiasis in Infants.

(5) Fundamental Biology

  • Schistosome population genetics and makers for drug resistance.

  • Host-parasite interactions and the impact of control interventions.

  • Impact of hybridization between human and animal (cattle) schistosomes.

  • Biological control of snails.

As a researcher, you have been involved in a very large number of collaborations both personally as well as on behalf of Cameroon's Centre for Schistosomiasis and Parasitology. What have been the most important partnerships in achieving research and public health goals and which partnerships would you like to develop looking forward?

Over years I have been involved in a very large number of collaborations. I managed over thirty important international research projects funded by a wide variety of national and international governmental and non-governmental organisations, and UN organizations such as DFID, Wellcome Trust, European Union, USAID, Bill & Melinda Gates Foundation, and WHO. Without being exhaustive, the most important partnerships in achieving translational research to improve the control of devastating parasites have been: (i) the VLIR-Wellcome Trust-WHO/TDR projects in 1999 that contributed in setting up the Centre for Schistosomiasis and Parasitology; (ii) the EU-funded CONTRAST project in 2006 that allowed to optimize schistosomiasis control and transmission surveillance in sub-Saharan Africa through a multidisciplinary alliance; (iii) the ongoing DFID-funded COUNTDOWN project on NTDs, the BMGF/Grand Challenges Exploration project, and the China-Africa cooperation for the elimination of schistosomiasis.

We wish all ongoing projects and partnerships listed above to be further developed and significantly expanded in order to achieve our research and public health goals, i.e. the elimination of NTDs in Cameroon. Considering the immensity of the challenges, we also wish the development of new projects and partnerships.

……………………………………………………...

For more information please contact:

Pr. Louis Albert Tchuem Tchuenté

University of Yaoundé & Centrefor Schistosomiasis and Parasitology

E: tchuemtchuente@schisto.com

#diseasesurveillance #mapping #Cameroon #parasitology #onchocerciasis #lymphaticfilariasis #trachoma #Guineaworm #HumanAfricanTrypanosomiasis #HAT #Buruliulcer #leprosy #leishmaniasis #yaws #STH #deworming #MDA #massdrugadministration #comorbidity #coinfections #schistosomiasis

The International Society for Neglected Tropical Diseases

© 2019 International Society for Neglected Tropical Diseases