Filariasis and transfusion-associated risk: a literature review

Diagnosis, management and prevention of loiasis: guideline of the German Society for Tropical Medicine, Travel Medicine, and Global Health (DTG)

Loiasis is a complex filarial infection endemic in Central Africa and parts of West Africa. Loa loa is transmitted by the deer fly Chrysops dimidiata and C. silacea. The clinical manifestation of the disease is highly variable ranging from asymptomatic infection, symptomatic disease, to life-threatening complications. The diagnosis of L. loa infection is challenging due to a significant proportion of occult infections and a lack of reliable point of care tests. While diethylcarbamazine is the gold standard for curative treatment in many non-endemic countries, its use is limited in endemic regions due to its propensity for severe adverse drug reactions that may occasionally lead to life threatening complications. Alternative treatment regimens have specific indications and limitations in the treatment of loiasis. In this guideline, issued by the German Society for Tropical Medicine, Travel Medicine, and Global Health, recommendations for the diagnosis, management, treatment, and prevention of loiasis are provided based on the currently available best evidence, and gaps in our understanding are highlighted.

An Overview of the Management of Mansonellosis

Mansonellosis is caused by three filarial parasite species from the genus Mansonella that commonly produce chronic human microfilaraemias: M. ozzardi, M. perstans and M. streptocerca. The disease is widespread in Africa, the Caribbean and South and Central America, and although it is typically asymptomatic it has been associated with mild pathologies including leg-chills, joint-pains, headaches, fevers, and corneal lesions. No robust mansonellosis disease burden estimates have yet been made and the impact the disease has on blood bank stocks and the monitoring of other filarial diseases is not thought to be of sufficient public health importance to justify dedicated disease management interventions. Mansonellosis´s Ceratopogonidae and Simuliidae vectors are not targeted by other control programmes and because of their small size and out-door biting habits are unlikely to be affected by interventions targeting other disease vectors like mosquitoes. The ivermectin and mebendazole-based mass drug administration (iMDA and mMDA) treatment regimens deployed by the WHO´s Elimination of Neglected Tropical Diseases (ESPEN) programme and its forerunners have, however, likely impacted significantly on the mansonellosis disease burden, principally by reducing the transmission of M. streptocerca in Africa. The increasingly popular plan of using iMDA to control malaria could also affect M. ozzardi parasite prevalence and transmission in Latin America in the future. However, a potentially far greater mansonellosis disease burden impact is likely to come from short-course curative anti-Wolbachia therapeutics, which are presently being developed for onchocerciasis and lymphatic filariasis treatment. Even if the WHO´s ESPEN programme does not choose to deploy these drugs in MDA interventions, they have the potential to dramatically increase the financial and logistical feasibility of effective mansonellosis management. There is, thus, now a fresh and urgent need to better characterise the disease burden and eco-epidemiology of mansonellosis so that effective management programmes can be designed, advocated for and implemented.