Available data regarding the distribution, prevalence and severity of various diseases are based on the performance and operational characteristics of the diagnostic techniques applied; a fact particularly apparent in the study of helminth infections. An important lesson learnt from the efforts to rein in dracunculiasis, lymphatic filariasis and schistosomiasis is that the diagnostic approach changes as further progress is made towards control and ultimate elimination of the disease. This insight prompted the opinion presented here, which highlights diagnostic dilemmas in helminthology related to the stage of control achieved, and sets out some research needs.Key words: helminth infections, diagnosis, control, elimination, microscopy, serology, specificity, sensitivity, prevalence Choice of diagnostic assaysNew and ambitious goals have been set for the control of infectious diseases in the developing world by governments and international donor agencies in collaboration with the World Health Organization (WHO). Significant progress has been made but there is a tendency to emphasize mainly drug treatment, and also vaccines, while the importance of quality-assured diagnostic tests is often neglected [1]. Yet, the more successful a control programme becomes, the more critical is the need for an accurate assessment of the epidemiological situation.The helminthic diseases require diverse diagnostic approaches. For example, while serology constitute a valuable adjunct to the clinical diagnosis of echinococcosis, trichinellosis and toxocariasis [2], the local elimination of various helminth infections such as dracunculiasis [3], lymphatic filariasis [4,5] and schistosomiasis [4,6,7] highlights the need for adjusting the diagnostic capability to the different stages of active control.The focus of this opinion article is on schistosomiasis and the main soil-transmitted helminthiases (ascariasis, hookworm disease and trichuriasis) because these diseases are still widespread [8][9][10], while activities to control them have gained momentum due to the World Health Assembly resolution WHA54.19 of May 2001, which urges member states to regularly treat at least 75% of school-aged children and other high-risk groups with praziquantel against schistosomiasis and albendazole/mebendazole against soil-transmitted helminthiases [11].The food-borne trematodiases (e.g. clonorchiasis, fascioliasis, opisthorchiasis and paragonimiasis) are also discussed as this group comprises serious, yet truly neglected tropical diseases which, in addition to their veterinary significance, constitute an emerging public health threat in many parts of the world [12][13][14][15][16].The choice of a diagnostic assay should be governed by the objective of the activity.Indeed, the proper diagnosis of an infection is paramount for all aspects of its prevention and control. Moreover, the evaluation of efficacy and community-effectiveness of interventions, verification of local disease elimination and early detection of resurgence strongly depends o...

Background Taenia solium cysticercosis/taeniosis is emerging as a serious public health and economic problem in many developing countries. This study was conducted to determine prevalence and risk factors of human T. solium infections in Mbeya Region, Tanzania.Methods and FindingsA cross-sectional survey was conducted in 13 villages of Mbozi district in 2009. Sera of 830 people (mean 37.9±11.3 years (SD); 43% females) were tested for circulating cysticerci antigen (Ag-ELISA) and antibody (Ab-ELISA). A subset of persons found seropositive by Ag-ELISA underwent computed tomography (CT) scan of the brain for evidence of neurocysticercosis. Stool samples from 820 of the same participants were tested for taeniosis by copro-antigens (copro-Ag-ELISA) and formol-ether concentration technique. Cases of T. solium taeniosis were confirmed serologically by EITB assay (rES38). A questionnaire was used for identification of risk factors. Active cysticercosis by positive Ag-ELISA was found in 139 (16.7%) persons while anti-cysticercal antibodies were detected in 376 (45.3%) persons by Ab-ELISA. Among 55 persons positive for Ag-ELISA undergoing CT scan, 30 (54.6%) were found to have structures in the brain suggestive of neurocysticercosis. Using faecal analysis, 43 (5.2%) stool samples tested positive for taeniosis by copro-Ag-ELISA while Taenia eggs were detected in 9 (1.1%) stool samples by routine coprology. Antibodies specifically against adult T. solium were detected in 34 copro-Ag-ELISA positive participants by EITB (rES38) indicating T. solium taeniosis prevalence of 4.1%. Increasing age and hand washing by dipping in contrast to using running water, were found associated with Ag-ELISA seropositivity by logistic regression. Gender (higher risk in females) and water source were risk factors associated with Ab-ELISA seropositivity. Reported symptoms of chronic severe headaches and history of epileptic seizures were found associated with positive Ag-ELISA (p≤0.05).ConclusionThe present study indicates T. solium infection in humans is highly endemic in the southern highlands of Tanzania.

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Taenia solium is an important zoonosis in many developing countries. Cysticercosis poses a serious public health risk and incurs sizeable economic losses to pig production. Because data on the epidemiology of porcine cysticercosis in Mozambique are scarce, the present study was conducted to determine the prevalence and risk factors for porcine cysticercosis. A cross-sectional survey was carried out in 11 villages in Angónia district, Tete province in northwestern Mozambique. Between September and November, 2007, a total of 661 pigs were tested serologically and examined by tongue inspection. Serum samples were tested for the presence of circulating parasite antigen using a monoclonal antibody-based sandwich enzyme-linked immunosorbent assay (Ag-ELISA). In addition, a questionnaire survey to collect information on pig production, occurrence and transmission of porcine cysticercosis, risk factors and awareness of porcine cysticercosis was conducted in the selected households from which pigs were sampled. Two hundred thirty-one samples (34.9%) were found positive by the Ag-ELISA, while by tongue inspection on the same animals cysticerci were detected in 84 pigs (12.7%). Increasing age (OR = 1.63; 95% CI = 1.13–2.37) and free-range pig husbandry system (OR = 3.81; 95% CI = 2.08–7.06) were important risk factors for porcine cysticercosis in the district. The present findings indicate that porcine cysticercosis is endemic in the region, and that increasing pig age and pig husbandry practices contribute significantly to porcine cysticercosis transmission. Further epidemiological studies on the prevalence and transmission of porcine cysticercosis in rural communities in Mozambique are needed to enable collection of more baseline data and implementation of effective control strategies within the country.

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