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Loa Loa: a New Rapid Assessment Tool // g No. 66 October 2001 TDR UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) CONTENTS KEYNOTE ARTICLE 3 TDR participates in major WHO initiative Loa loa: A new rapid 4 The filariases: TDR studies help define parameters for control assessment tool 5 Biosocial research and the TDR agenda Rapid development of WHO/TDR an urgently needed 8 Does inequality matter? tool puts onchocercia- sis control operations 9 Multilateral Initiative back on track in cen- on Malaria in Africa (MIM) tral Africa. 10 Dengue update 10 Dr Remme of TDR awarded the Eijkman Medal 11 TDR co-worker awarded for contribution to A simple method that can be used to rapidly An interviewer mine how heavy (or ‘intense’) TB control assess which communities are at risk of develop- asks about history Loa infection is, and so a sim- of eye worm. ing severe adverse reactions following treatment ple method was sought. 11 TDR research with ivermectin for onchocerciasis, due to co- Earlier studies2 had indicated collaborator honoured infection with ‘eyeworm’ (or Loa loa), has been that a correlation exists between intensity of substantiated in a TDR multicountry study. After infection and prevalence, that there are preva- analysis of the results at a workshop in Septem- lence thresholds above which the risk of severe 12 Awards in Basic and ber 2001, the method was immediately taken up reactions becomes too high for routine treat- Strategic Research by the African Programme for Onchocerciasis ment with ivermectin. High-risk villages, where Control (APOC) for use alongside community adverse reactions may be anticipated, were indi- 16 Staff news: directed treatment with ivermectin (CDTI). cated to be those where there is more than 20% comings and goings The need for such a method was urgent. In some prevalence of Loa infection, or more than 5% areas of Cameroon where both diseases prevalence of heavy Loa infection (more than 17 Chagas Disease (onchocerciasis and loiasis) are endemic, the use 8000 microfilariae/ml blood). The current study, of CDTI, and hence onchocerciasis control, had carried out in over 100 villages in Nigeria and virtually come to a standstill because of the risk Cameroon, confirmed that a very clear correla- 18 Publications of severe adverse reactions. The reactions occur tion does indeed exist between prevalence and in persons heavily infected with loiasis and intensity of infection. 19 Net news include potentially fatal degenerative effects in A number of different rapid assessment the brain.1 However, under field conditions it is procedures (RAPs) for determining prevalence 20 Deadlines not at all practical to do blood surveys to deter- were compared, including history of > (next page) www.who.int/tdr // g ... A new rapid assessment tool (continued)> eyeworm (whether worms moving along the white of the lower part of the eye have ever been experienced) and Calabar Swelling (whether swellings under the skin which change position or disappear have ever been experienced). All RAPs showed correlation with level of endemicity of Loa, although the best performance was with the RAP based on eyeworm. A prevalence of 40% or more of eyeworm in a community, confirmed by showing a photograph of a worm in the lower part of an eye, was identified as the threshold above which there is a high risk of adverse reactions during CDTI; conversely, where history of eyeworm is less than 40%, there need be no worry concerning mass treatment with ivermectin. The procedure, called RAPLOA, is 100% sensitive and more than 90% specific. This simple method is effective because eyeworm is such a well known infection in endemic communities that they have their own local names for the condition. As recommended by APOC, TDR is now developing standardized guide- lines for the application of RAPLOA, and APOC intends to apply the TDRnews RAPLOA method soon in several areas where CDTI is planned and where Loa loa is potentially endemic. Further research will aim at devel- is published three times Loa loa worm a year by the UNDP/World moving along the white oping a rapid mapping method, possibly through combining RAPLOA with Bank/WHO Special of the eye. an environmental modelling system under development by the Liverpool Programme for Research School of Tropical Medicine. Due to the rapid development of RAPLOA and Training in Tropical (a mere nine months went by between the protocol development work- Diseases (TDR). shop and application of the results in practice), onchocerciasis control Full article text available operations in Central Africa can soon go full speed ahead again. on the TDR website. All material submitted to TDRnews undergoes edito- Correlation between history of eye worm rial review. Articles and and prevalence of Loa loa illustrations published in TDRnews which are not copyrighted may be repro- duced, provided credit is given to TDR and provided such reproduction is not used for commercial purposes. Articles do not necessarily reflect the views of WHO. Managing editor Nina Mattock Production team Andy Crump Cathy Needham Design and layout Lisa Schwarb Eastern Cameroon Western Cameroon Cross River Nigeria Tel. (+41-22) 791-3725 CONTACTS 1 Fax Gardon J et al. Serious reactions after mass (+41-22) 791-4854 Dr Hans Remme treatment of onchocerciasis E-mail with ivermectin in an area TDR [email protected] endemic for Loa loa infec- tion. Lancet, July 5 1997, Web Tel: (+41-22) 791-3815 350(9070): 18-22. www.who.int/tdr Fax: (+41-22) 791-3737 2 Boussinesq M et al. Address Relationships between the TDR E-mail: [email protected] prevalence and intensity of World Health Organization Loa loa infection in the Cen- tral province of Cameroon. Avenue Appia 20 Annals of Tropical Medicine 1211 Geneva 27 and Parasitology, 2001, Switzerland 95(5): 495-507. 2 • TDRnews • No 66 • OCTOBER 2001 // g RESEARCH CAPACITY STRENGTHENING TDR participates in major WHO initiative WHO and six of the Free internet access to would like to par- biggest medical jour- top international medical ticipate in this initia- nal publishers tive, and how you announced an journals–WHO invites would make the important initiative medical schools and most of your partic- in July 2001. Medical research institutes in low ipation. There is no schools and research income countries to seize restriction on the institutes in low number of institu- income countries the opportunity tions that can par- are to get free (or ticipate, so please low cost, depending on GNP per also suggest other organizations in capita) full-text access through the your country and region that might Internet to nearly 1500 top interna- benefit from this chance too. tional medical journals. “It is per- To be eligible, you/your institute haps the biggest step ever taken must exist in a low income country towards reducing the health infor- and be working in the area of health mation gap between rich and poor or biomedicine, e.g. you will likely countries” said Dr Gro Harlem be from a: Brundtland, Director-General of • school of medicine, nursing, CONTACTS WHO, at the signing of the State- public health, pharmacy, Mrs Barbara Aronson ment of Intent by senior executives biomedical sciences, or social WHO information and of the publishers. sciences. library services It is planned that the initiative will • university (particularly one offer- begin in January 2002, and that ing graduate studies in biomedical Tel: (41-22) 791-2034 progress will be monitored for disciplines). Fax: (+41-22) 791-4854 three years. TDR will help in imple- • research institute. E-mail: menting the initiative (known as • government office. [email protected] Health InterNetwork Access to This initiative is expected to have Research Initiative, see TDRnews implications that extend beyond No. 64) because of its commitment access to information. It is envi- Steven Wayling to capacity building. sioned that better and timely infor- Manager–Research Thus WHO would be interested to mation will increase the capacity of Training hear from any of you, our collabora- scientists and health care workers tors, who could make use of this from low income countries to par- WHO/TDR opportunity. We would like to ticipate in the global research agen- Tel: (41-22) 791-3909 know how you/your institute would da, to better set national research Fax: (+41-22) 791-4854 ensure the widest possible access to and health care priorities, and to E-mail: the journals. We need to know increase countries' self-reliance in what your institute can provide and developing evidenced-based strate- [email protected] what it lacks. Perhaps you already gies and tools for the prevention, have high-speed Internet access, and control and treatment of disease. possibly a LAN, as well as the neces- We look forward to hearing from sary hardware (e.g. computers, you. For further information, printers, toner, paper). Perhaps you need training for trainers on Inter- please see WHO press net and information management release at: skills, or on scientific writing and http://www.who.int/ publishing. Whatever your needs inf-pr-2001/en/ and aspirations, please contact us by e-mail to let us know that you pr2001-32.html TDRnews • No 66 • OCTOBER 2001 • 3 // g INTERVENTION DEVELOPMENT AND IMPLEMENTATION RESEARCH The filariases: TDR studies help define parameters for control TDR research is helping to elic- Simulation model gives sentative, so further analysis was it answers to a number of ques- new insights into optimal made of patterns of infection by tions posed by filariases control age. The most common pattern treatment strategies programmes. was that of a plateau, not a In onchocerciasis, for example, for filariasis, and simple decline, in prevalence after a cer- where control programmes are foot care is shown to be tain age; thus Pondicherry was making headway towards elimi- a sustainable and cost- found to be an exception rather nating the disease through com- than the rule.
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