Elimination of bancroftian filariasis (Wuchereria bancrofti) in Santa Catarina state, Brazil

Abstract

SummaryDuring the 1950s, three foci of Wuchereria bancrofti transmission were identified in the State of Santa Catarina, Brazil. In Florianópolis, São José da Ponta Grossa and Barra da Laguna community treatment of bancroftian filariasis with diethylcarbamazine (DEC) was performed using two distinct approaches, without vector control or improvements in sanitation. In two of the three communities only microfilaraemic individuals were treated, while in Barra da Laguna the entire population received DEC treatment regardless of their infection status. In both cases, transmission of the parasite was blocked and no new cases were detected in all localities for up to 10 years. Recently, a new survey in São José da Ponta Grossa and Barra communities revealed no microfilaria-positive individuals, including residents that were positive in the 1950s. These data confirm that transmission of W. bancrofti was interrupted in Santa Catarina, and mass treatment appears to be more effective than treatment of microfilaraemic individuals only.

The Global Programme to Eliminate Lymphatic Filariasis: Health Impact after 8 Years

“…While programmatic evidence exists that effective transmission of LF might cease very soon after the initiation of MDA activities [22],[23],[36], entomologic studies linked with anti-filarial single-dose treatment regimens indicate that the decline in vector infection may be more gradual [22], [23], [37]–[41]. Since the availability of such data is too limited (with respect to vector species, collection techniques, parasite assessments, LF prevalence, treatment regimens, and other variables) to give precise estimates of post-MDA changes in vector infection, data from available studies [22], [23], [37]–[41] were pooled, yielding a relationship that describes an ‘average’ rate-of-decline of vector infection; namely, declines to 50%, 25%, 12%, 6% and 0% of pre-treatment levels following each of the first 5 MDAs, respectively.…”

Resurgence in filarial transmission after withdrawal of mass drug administration and the relationship between antigenaemia and microfilaraemia – a longitudinal study

“…1989). Elimination was recorded in some islands of Brazil, with prolonged chemotherapy with DEC in the form of mass treatment, with community support (Schlemper et al . 2000).…”

Prospects for Elimination of Bancroftian Filariasis by Mass Drug Treatment in Pondicherry, India: A Simulation Study

“…Therefore, it is uncertain whether continuation of mass treatment would lead to elimination. In a Wuchereria bancrofti-positive locality in Brazil, lymphatic filariasis was virtually eliminated after 7 years of 6-monthly mass treatment [13], whereas in French Polynesia transmission continued despite long-term intensive control [14,15].…”