Studies Summary

Soil Transmitted Helminths (STH) such as Ascaris lumbricoides, hookworms, and Trichuris trichiura are intestinal parasites that require fecal contamination of the environment for transmission. The number of infected individuals worldwide for Ascaris, hookworm and Trichuris are estimated to be 1000 million, 650 million, and 700 million, respectively. These parasites have their highest health impacts in children; they impair growth, retard cognitive development, and cause severe anemia.

Drugs used for other parasitic infections: lymphatic filariasis and onchocerciasis through mass drug administration (MDA) programs are also active against STH. Suppression of STH is an important ancillary benefit of MDA programs.Conventional de-worming campaigns usually target school-aged children, and they have limited impact on transmission. The DOLF project is studying the effects of treating total populations to test whether MDA can reduce STH infection intensities and reinfection rates. In addition, DOLF is using the routine assessments of treatment for sample collection to improve the diagnosis of STH (Fischer 2018, Rosa 2018).

Effect of Semiannual vs Annual MDA for LF on

Studies in Liberia (2 sites), Cote d’Ivoire, Indonesia and PNG indicate that in some areas MDA reduces the density of STH infection and may temporarily reduce prevalence. However, 12 months after the last MDA the difference between semiannual and annual MDA has mostly vanished. The effect of MDA to eliminate LF and Oncho on STH appears variable and to depend on pretreatment prevalence and the local epidemiology.

Preparation of Kato Katz slides for STH detection in Liberia.

Preparation of Kato Katz slides for STH detection in Liberia.

Effect of Semiannual MDA with Albendazole on STH

Semiannual MDA with Albendazole is effective in reducing STH. Studies from the Republic of Congo indicated in areas with low hookworm prevalence it may be even possible to eliminate this infection (Pion et. al. 2017, 2015).

Effect of IDA for LF on STH

Studies on the effect of IDA on STH are currently performed in eastern Indonesia and Papua New Guinea. Since ivermectin has been rarely used in for MDA in this part of the world we expect exciting new results.



Capillaria Ova and Diagnosis of Trichuris trichiura Infection in Humans by Kato-Katz Smear, Liberia
K Fischer, A Gankpala, L Gankpala, FK Bolay, KC Curtis, GJ Weil, PU Fischer
Emerg Infect Dis. 2018;24(8), 1551-1554

Differential human gut microbiome assemblages during soil-transmitted helminth infections in Indonesia and Liberia
BA Rosa, T Supali, L. Gankpala, Y Djuardi, E Sartono, Y Zhou, K Fischer, J Martin, R Tyagi, FK Bolay, PU Fischer, M Yazdanbakhsh, M Mitreva
Microbiome. 2018;6(33)

Effect of 3 years of biannual mass drug administration with albendazole on lymphatic filariasis and soil-transmitted helminth infections: a community-based study in Republic of the Congo
SDS Pion, CB Chenaiz, GJ Weil, PU Fischer, F Missamou, M Boussinesq
Lancet Infect Dis. 2017;17(7):763-769

The Impact of Two Semi-annual Treatments with Albendazole Alone on Lymphatic Filariasis and Soil-Transmitted Helminth Infections: A Community-based Study in the Republic of Congo
SDS Pion, CB Chesnais, J Bopda, F Louya, PU Fischer, AC Majewski, GJ Weil, M Boussinesq, F Missamou
Am J Trop Med Hyg. 2015;92(5):959-966