A retrospective and a longitudinal survey were carried out at the abattoir of Niamey. Results showed a highly significant difference in suspected tuberculosis (TB) gross lesions among different animal species (P < 0.0001). The proportion of carcasses with TB-like lesions was 0.19% among cattle, 0.11% among camels, 0.001% among sheep and 0.0006% among goats. In cattle, cows are significantly more affected than the other categories (P < 0.001). Also in cattle, TB-like lesions are mostly localized in the lungs (92.77%) followed by the lymph nodes (50.87%) and the liver (32.40%). The prevalence of gross lesions compatible with bovine TB (BTB) is strongly influenced by the season (P < 0.0001), is closely correlated with the origin of the animals (P < 0.001) and has a negative impact on the weight of affected animals (P < 0.0001). Sixty-two samples of suspected TB gross lesions were subject to microbiological analysis and molecular typing of strains. Mycobacterium bovis was identified in 18 animals showing five different spoligotypes, belonging to type 'African 1' previously identified in Central and West Africa. In addition, a profile (SB1982) not previously reported distinguished by the absence of spacers 3, 4, 9, 16, 22, 30 and 39-43 has been characterized in this study. To assess risk factors for BTB transmission, a questionnaire on animal husbandry practices, food habits, and clinical signs of TB in animals and humans was submitted to the heads of 1131 randomly selected households. The main risk factors identified are consumption of unpasteurized milk (91%) and lack of hygiene within households (32-74%). Clinical signs that could be attributed to TB were also reported both in humans and in animals of the households.

Background Information on insecticide resistance and the mechanisms driving it in the major malaria vectors is grossly lacking in Niger Republic, thus hindering control efforts. To facilitate evidence-based malaria control, the role of Anopheles coluzzii population from southern Niger, in malaria transmission, its insecticides resistance profile and the molecular mechanisms driving the resistance were characterized. Methods Blood fed female Anopheles gambiae sensu lato resting indoor were collected at Tessaoua, Niger. Source of blood was established using PCR and infection with Plasmodium determined using TaqMan assay. Resistance profile was established with the major public health insecticides, and resistance intensity determined with deltamethrin. Synergist assays were conducted with piperonyl butoxide and diethyl maleate. Presence of L1014F and L1014S knockdown resistance ( kdr ) mutations in the voltage-gated sodium channel (VGSC) was investigated using TaqMan genotyping, and strength of selection pressure acting on the Anopheles populations determined by assessing the genetic diversity of a fragment spanning exon-20 of the VGSC from alive and dead females. Results High human blood index (96%) and high Plasmodium falciparum infection (~ 13%) was observed in the An. coluzzii population. Also, a single mosquito was found infected with Plasmodium vivax. High pyrethroid and organochloride resistance was observed with mortalities of less than 20% for deltamethrin, permethrin, α-cypermethrin, and DDT. A high LD 50 (156.65 min) was obtained for deltamethrin, with a resistance ratio of ~ 47.18 compared to the susceptible Ngoussou colony. Moderate carbamate resistance was observed, and a full susceptibility to organophosphates recorded. Synergist bioassays with piperonyl butoxide and diethyl maleate significantly recovered deltamethrin and DDT susceptibility, respectively implicating CYP450 s (mortality = 82%, χ 2 = 84.51, p < 0.0001) and glutathione S-transferases (mortality = 58%, χ 2 = 33.96, p < 0.001) in resistance. A high frequency of 1014F kdr mutation (82%) was established, with significant difference in genotype distribution associated with permethrin resistance [odds ratio = 7.71 (95% CI 2.43–14.53, χ 2 = 13.67, p = 0.001]. Sequencing of intron-1 of the voltage-gated sodium channel (VGSC) revealed a low genetic diversity. Conclusion High pyrethroid resistance highlight the challenges to the effectiveness of the pyrethroids-based ITNs and indoor residual spraying (IRS) against An. coluzzii in Niger. The pyrethroids-synergists LLINs and...

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Background Mass distribution of insecticide treated nets (ITNs) is the principal malaria vector control strategy adopted by Niger. To better inform on the most appropriate ITNs to distribute, the Niger National Malaria Control Programme (NMCP), with the support of the U.S. President’s Malaria Initiative and its partners, conducted insecticide resistance monitoring in sixteen sites selected across the country. Methods The susceptibility of Anopheles gambiae sensu lato (s.l.) to chlorfenapyr and pyrethroid insecticides was investigated in nine sites in 2019 and fifteen sites in 2020, including eightfrom the previous year. The susceptibility status, pyrethroid resistance intensity at 5 and 10 times the diagnostic concentrations, and piperonyl butoxide (PBO) synergism with diagnostic concentrations of deltamethrin, permethrin and alpha-cypermethrin were assessed using WHO bioassays. Two doses (100 and 200 µg/bottle) of chlorfenapyr were tested using the CDC bottle assay method. Species composition and allele frequencies for knock-down resistance (kdr-west and kdr-east) and acetylcholinesterase (ace-1) mutations were further characterized using polymerase chain reaction (PCR). Results High resistance to all pyrethroids tested was observed in all sixteen sites during both years. Pre-exposure to PBO substantially increased susceptibility with average increases in mortality from 30 to 70% for deltamethrin, 0 to 60% for permethrin, and 5 to 70% for alpha-cypermethrin. Susceptibility to chlorfenapyr (100 ug/bottle) was recorded in all sites except in Tessaoua and Magaria where susceptibility was recorded at the dose of 200 ug/bottle. The kdr-e allele, investigated for the first time, was detected in the country. Both kdr-w and kdr-e were present in all 15 sites surveyed in 2020, at frequencies between 0.46–0.81 and 0.41–0.87, respectively. An. coluzzii was the predominant malaria vector species in the 16 sites surveyed for insecticide susceptibility followed by An. gambiae s.s. and An. arabiensis. Conclusion The data collected showed high resistance to pyrethroids with the involvement of various resistance mechanisms, which will guide the NMCP in making evidence-based decisions to better adapt vector control strategies and insecticide resistance management in Niger, starting with the introduction of new generation ITNs such as interceptor G2 and PBO ITNs for mass distribution campaigns, by targeting sites where the vector population showed susceptibility to chlorfenapyr or increased mortality using PBO synergism.