Fine scale spatial investigation of multiple insecticide resistance and underlying target-site and metabolic mechanisms in Anopheles gambiae in central Côte d’Ivoire

Routine monitoring of occurrence, levels and mechanisms of insecticide resistance informs effective management strategies, and should be used to assess the effect of new tools on resistance. As part of a cluster randomised controlled trial evaluating a novel insecticide-based intervention in central Côte d’Ivoire, we assessed resistance and its underlying mechanisms in Anopheles gambiae populations from a subset of trial villages. Resistance to multiple insecticides in An. gambiae s.s. and An. coluzzii was detected across villages, with dose–response assays demonstrating extremely high resistance intensity to the pyrethroid deltamethrin (> 1,500-fold), and mortality following exposure to pyrethroid-treated bednets was low (< 30% mortality in cone bioassays). The 1014F kdr mutation was almost fixed (≥ 90%) in all villages but the 1575Y kdr-amplifying mutation was relatively rare (< 15%). The carbamate and organophosphate resistance-associated Ace-1 G119S mutation was also detected at moderate frequencies (22–43%). Transcriptome analysis identified overexpression of P450 genes known to confer pyrethroid resistance (Cyp9K1, Cyp6P3, and Cyp6M2), and also a carboxylesterase (COEAE1F) as major candidates. Cyp6P3 expression was high but variable (up to 33-fold) and correlated positively with deltamethrin resistance intensity across villages (r2 = 0.78, P = 0.02). Tools and strategies to mitigate the extreme and multiple resistance provided by these mechanisms are required in this area to avoid future control failures

Open-Label Randomized Trial of Oral Trimethoprim-Sulfamethoxazole, Doxycycline, and Chloramphenicol Compared with Trimethoprim-Sulfamethoxazole and Doxycycline for Maintenance Therapy of Melioidosis

Melioidosis (infection caused by Burkholderia pseudomallei) requires a prolonged course of oral antibiotics following initial intravenous therapy to reduce the risk of relapse after cessation of treatment. The current recommendation is a four-drug regimen (trimethoprim [TMP], sulfamethoxazole [SMX], doxycycline, and chloramphenicol) and a total treatment time of 12 to 20 weeks. Drug side effects are common; the aim of this study was to compare the efficacy and tolerance of the four-drug regimen with a three-drug regimen (TMP-SMX and doxycycline). An open-label, randomized trial was conducted in northeast Thailand. A total of 180 adult Thai patients were enrolled, of which 91 were allocated to the four-drug regimen and 89 to the three-drug regimen. The trial was terminated early due to poor drug tolerance, particularly of the four-drug regimen. The culture-confirmed relapse rates at 1 year were 6.6% and 5.6% for the four- and three-drug regimens, respectively (P = 0.79). The three-drug regimen was better tolerated than the four-drug regimen; 36% of patients receiving four drugs and 19% of patients receiving three drugs required a switch in therapy due to side effects (P = 0.01). The duration of oral therapy was significantly associated with relapse; after adjustment for confounders, patients receiving less than 12 weeks of oral therapy had a 5.7-fold increase of relapse or death. A combination of TMP-SMX and doxycycline is as effective as and better tolerated than the conventional four-drug regimen for the oral treatment phase of melioidosis

J Travel Med

Background: International travel has increased in the past few decades, placing more travellers at risk of acquiring systemic endemic mycoses. There are limited published data on systemic endemic mycoses among international travellers. We report epidemiological characteristics of non-migrant, international travellers who acquired systemic endemic mycoses during travel. Methods: We analysed records of non-migrant international travellers with a confirmed diagnosis of histoplasmosis, coccidioidomycosis, paracoccidioidomycosis, blastomycosis or talaromycosis reported from 1997 through 2017 to GeoSentinel, a global surveillance network now consisting of 70 travel or tropical medicine centres in 31 countries. Results: Sixty-nine records met the inclusion criteria. Histoplasmosis was most frequently reported; the 51 travellers with histoplasmosis had the lowest median age (30 years; range: 8-85) and shortest median duration of travel (12 days; range: 5-154). Coccidioidomycosis was reported in 14 travellers; travellers with coccidioidomycosis were older (median 62 years; range: 22-78) and had the longest median number of days between return from travel and presentation to a GeoSentinel site (55 days; range: 17-273). Almost all travellers with coccidioidomycosis were exposed in the USA. Other systemic endemic mycoses were less frequently reported, including blastomycosis (three travellers) and talaromycosis (one traveller). Conclusions: Although relatively rare, systemic endemic mycoses should be considered as potential travel-related infections in non-migrant international travellers. Epidemiological exposures should be used to guide diagnostic evaluations and treatment