Projects

Identification of serosurveilance antigens for schistosomiasis

To identify antigens that can be produced as recombinant proteins and to document elimination of schistosomiasis.

To identify antigens that differentiate between infections with Schistosoma mansoni and Schistosoma haematobium and that can be used in an ELISA, lateral flow assay or multiplex format.

Diseases: Schistosomiasis

Trachoma in the Western Pacific

Determine whether current or historic C. trachomatis (Ct) infection can be detected, and whether it is associated with clinical signs of ‘trachomatous inflammation – follicular’ (TF) in Vanuatu and Kiribati

Determine the utility of infection testing as a tool for operational surveillance and impact assessment in trachoma-endemic environments.

Countries: Kiribati | Vanuatu
Diseases: Trachoma

LFTAS + Biplex + DBS in Oncho endemic areas in Cameroon

To assess if transmission assessment surveys (TAS) for lymphatic filariasis (LF) are a feasible platform to integrate transmission assessment for onchocerciasis, using the same age group (6-7 years old) and the same prevalence threshold (<2%) that the LF programs utilize.

1. To perform the TAS for stopping LF MDA and use it as platform for Oncho impact assessment.
2. To assess the level of endemicity of Oncho following at least five rounds of MDA in hypo, meso and hyper endemic districts.
3. To study the performance of the Wb123/Ov16 Biplex rapid diagnostic test (RDT) to assess Oncho and LF transmission interruption.

 

Preliminary study findings:

  • This study involved an integrated impact assessment of onchocerciasis and lymphatic filariasis using the LF TAS platform and the serologic rapid text Biplex in the Northern area of Cameroon.
  • The study sites covered 31 health districts in the Far-North and North regions, constituting nine evaluation units, for which TAS1 was planned.
  • Community-based cluster surveys were conducted collecting GPS and demographic information, lymphedema symptoms, and testing by FTS, by Wb123/Ov16 Biplex, and by Night Blood Smear of 6 and 7 year old children.
  • In total, 13,957 children were recruited from 267 enumeration units (villages).
  • Ten children showed evidence of LF exposure or infection: 4 were positive by FTS and 6 were positive by Wb123 (via biplex).  No children tested positive for both FTS and Wb123. 
  • Night blood smears - conducted in children who were positive by FTS and by Wb123/Ov16 Biplex - were all negative.
  • For onchocerciasis, one individual was Ov16 positive (by Biplex).

In conclusion, all nine evaluation units passed the TAS1 assessment. As for onchocerciasis, study results are consistent with the previous hypo-endemic status of the area.

Countries: Cameroon

Develop epidemiological and entomological methods to assess verification of transmission interruption of Onchocerciasis in Equatorial Guinea- Africa

After two decades of onchocerciasis control activities in Bioko island, transmission is expected to be interrupted. This study aims to demonstrate that WHO criteria to verify transmission interruption have been met. It also aims to standardize the reading of RDTs, particularly the FTS and Ov16, and reduce the potential for human error.

Preliminary Study Findings:

A cross-sectional study was conducted from September 2016 to January 2017. Participants were 5- to 9-year-old school children. Onchocerciasis/lymphatic Filariasis (LF, only in endemic districts) rapid diagnostic tests (RDTs) were performed. Blood spots were collected from RDT positive children and 10 percent of the RDT negatives to determine Ov16 and Wb123 IgG4 antibodies through enzyme-linked immunosorbent assay (ELISA). Skin snips were collected from RDT positives. Filarial detection was performed by PCR in positives and indeterminate sera. Black fly collection was carried out in traditional breeding sites. A total of 7,052 children, ranging from 5 to 9 years of age, were included in the study. Four children (0.06%) were Ov16 IgG4 RDT positives, but negative by ELISA Ov16, while 6 RDT negative children tested positive by ELISA. A total of 1,230 children from the Riaba and Baney districts were tested for LF. One child was Wb123 RDT positive (0.08%), but ELISA negative, while 3 RDT negative children were positive by Wb123 ELISA. All positive samples were negative by PCR for onchocerciasis and LF (in blood spot and skin snip). All fly collections and larval prospections in the traditional catching and prospection sites were negative.

Read more in Herrador et al.: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0006471

Countries: Equatorial Guinea

Assessment of LF status in Two Urban Settings of Benin (Cotonou and Porto-Novo)

To determine whether there is LF transmission in Cotonou and Porto-Novo, which are the two main urban locations of Benin where the LF status is undetermined. A study will be conducted to evaluate the prevalence of LF using antigenemia and antibody testing (FTS and Wb123). An entomological survey will be implemented to understand the dynamic of LF transmission and potential barriers to LF MDA in urban settings. 

Preliminary study findings:

  • While mass drug administration (MDA) in Benin is on track to eliminate LF in most endemic cities, 50 such cities – including the country’s largest cities, Cotonou and Porto Novo – never received treatements.
  • In 2016, more than 15 years after mapping, LF endemicity was re-evaluated in Cotonou and Porto Novo to put in place adequate strategies for LF elimination. This study constituted that re-mapping effort.
  • The various surveys, conducted in vectors and humans through collection of entomological and parasitological data, reveal an absence of LF transmission in Cotonou and Porto Novo.
  • The results demonstrate that the number of cities endemic for LF in Benin has dropped from 50 to 48.
  • However, the study revealed a lack of awareness of LF by residents and health workers, highlighting the need for more education and awareness raising on the disease.
Countries: Benin

Mapping LF-Loa Coendemicity in South Sudan

Mapping LF-Loa Coendemicity in South Sudan

Countries: South Sudan

Mapping LF-Loa Coendemicity in Angola

Mapping LF-Loa Coendemity

Countries: Angola

Mapping LF-Loa Coendemicity in Chad

Mapping LF-Loa Coendemicity

Countries: Chad

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