January 9, 2015
Filarial Antigenemia and Loa loa Night Blood Microfilaremia in an Area Without Bancroftian Filariasis in the Democratic Republic of Congo
Elimination of lymphatic filariasis from areas co-endemic for loiasis is a problem, because ivermectin cannot be safely used for mass drug administration. In this study from the Orientale region of the DRC we show that mapping of lymphatic filariasis distribution in these areas is also problematic because individuals with high Loa loa microfilaria densities may have a positive filarial antigen test result in the absence of W. bancrofti infection. Furthermore, L. loa can also reach high microfilaria numbers in night blood which complicates mapping using parasitological methods. Thus methods routinely used for LF mapping may not be reliable in areas in central Africa that are highly endemic for loiasis.
Confounding filarial antigen results.
A comprehensive assessment of lymphatic filariasis in Sri Lanka six years after cessation of mass drug administration
This study used several different tests for post-MDA surveillance in 19 sites in 8 districts in Sri Lanka. Low level persistence of LF was detected in all districts, and results suggested that transmission may be ongoing in several areas. Exposure monitoring (screening for anti-filarial antibodies in primary school children) and molecular xenomonitoring (detecting filarial DNA in mosquito vectors) were much more sensitive than TAS for detecting low level persistence of filariasis in Sri Lanka. These methods are complementary to TAS, and they are feasible for use by some national filariasis elimination programs.
A Case Study in Risk Factors for LF in the Republic of Congo
Using prevalence data collected from a DOLF study site in the Republic of Congo, Chesnais et. al., describe risk factors associated with lymphatic filariasis. In this study age, sex, and occupational-dependent exposure to mosquitoes were important risk factors.