03030nas a2200325   4500000000100000008004100001653001500042653001200057653001200069653003000081653002700111653001700138100002500155700001100180700001200191700001600203700001500219700001200234700001200246700001500258700001200273700001700285700001400302245012100316856007800437300000800515490000700523520216000530022001402690       2019                            d10aclustering10aleprosy10aMapping10aPost-exposure prophylaxis10aSingle dose rifampicin10aTransmission1 aOrtuño-Gutiérrez N1 aBaco A1 aBraet S1 aYounoussa A1 aMzembaba A1 aSalim Z1 aAmidy M1 aGrillone S1 aJong BC1 aRichardus JH1 aHasker EC00aClustering of leprosy beyond the household level in a highly endemic setting on the Comoros, an observational study.  uhttps://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-019-4116-y  a5010 v193 a<p><strong>BACKGROUND: </strong>The island of Anjouan (Comoros) is highly endemic for leprosy with an annual incidence of 5-10/10,000. In May/June, 2015 single-dose Rifampicin post-exposure prophylaxis (SDR-PEP) was administered to 269 close contacts of 70 leprosy-patients in four villages as a pilot programmatic intervention. Two years later we revisited the villages for follow-up investigations. The main aim of our study was to quantify spatial associations between reported leprosy cases before and after PEP implementation. A secondary aim was to assess the effect of this single round of SDR-PEP at the individual level.</p>

<p><strong>METHODS: </strong>We conducted door-to-door leprosy screening in all four villages in August/September, 2017. We screened all consenting individuals for leprosy and recorded geographic coordinates of their household. We also recorded whether they had received SDR-PEP and whether they had been diagnosed with leprosy, before or after the 2015 intervention. We fitted a Poisson model with leprosy as outcome and distance to the nearest pre-intervention case and SDR-PEP as predictors.</p>

<p><strong>RESULTS: </strong>During the survey we found 114 new cases among 5760 contacts screened (2.0% prevalence), in addition to the 39 cases detected in the two preceding years. We found statistically significant associations of incident leprosy with physical distance to index cases ranging from 2.4 (95% confidence interval (95% CI) 1.5-3.6) for household contacts to 1.8 (95% CI 1.3-2.5) for those living at 1-25 m, compared to individuals living at ≥75 m. The effect of SDR-PEP appeared protective but did not reach statistical significance due to the low numbers, with an incidence rate ratio (IRR) of 0.6 (95% CI 0.3-1.2) overall, and 0.5 (95% CI 0.2-1.3) when considering only household contacts.</p>

<p><strong>CONCLUSIONS: </strong>This pilot demonstrated an increased risk of leprosy in contacts beyond the household, therefore a wider circle should be considered for chemoprophylaxis. Baseline surveys and extended contact definitions are essential for improving SDR-PEP effectiveness.</p>
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