Stable high-density and maternally inherited Wolbachia infections in Anopheles moucheti and Anopheles demeilloni mosquitoes Highlights d High-density Wolbachia strains found in An. moucheti and An. demeilloni mosquitoes d Infections are visualized in the ovaries, and maternal transmission was observed d Sequencing at depths and coverages comparable to other known Wolbachia strains d Homologs of cytoplasmic incompatibility factor genes are present in both genomes

Tsetse transmit African trypanosomiasis, which is a disease fatal to both humans and animals. A vaccine to protect against this disease does not exist so transmission control relies on eliminating tsetse populations. Although neurotoxic insecticides are the gold standard for insect control, they negatively impact the environment and reduce populations of insect pollinator species. Here we present a promising, environment-friendly alternative to current insecticides that targets the insect tyrosine metabolism pathway. A bloodmeal contains high levels of tyrosine, which is toxic to haematophagous insects if it is not degraded and eliminated. RNA interference (RNAi) of either the first two enzymes in the tyrosine degradation pathway (tyrosine aminotransferase (TAT) and 4-hydroxyphenylpyruvate dioxygenase (HPPD)) was lethal to tsetse. Furthermore, nitisinone (NTBC), an FDA-approved tyrosine catabolism inhibitor, killed tsetse regardless if the drug was orally or topically applied. However, oral administration of NTBC to bumblebees did not affect their survival. Using a novel mathematical model, we show that NTBC could reduce the transmission of African trypanosomiasis in sub-Saharan Africa, thus accelerating current disease elimination programmes.

Insect-specific flaviviruses (ISFs), are a group of nonpathogenic flaviviruses that only infect insects. ISFs can have a high prevalence in mosquito populations, but their transmission routes are not well understood.

Significance Lymphatic filariasis caused by Wuchereria bancrofti , Brugia malayi , and Brugia timori affects 51 million people, leading to severe physical and mental disabilities. A mutualistic symbiosis between these filarial nematodes and Wolbachia bacteria has been exploited as a new curative treatment. Epidemiological modeling of anti- Wolbachia treatment assumes that transmission persists due to the lag phase before microfilariae (mf) become removed from circulation. Here, we show that Wolbachia -depleted mf cannot develop within the mosquito vector—a phenotype associated with down-regulation of B. malayi mf-specific chitinase, an enzyme essential for exsheathment. Our findings add to the broad range of host biological processes dependent on Wolbachia and suggest that anti- Wolbachia treatment mediates a more accelerated impact on elimination of lymphatic filariasis than currently predicted.

Skin snip evaluation for onchocerciasis has insufficient sensitivity when skin microfilarial (mf) densities are low, such as following ivermectin treatment. Mf density is suitable for assessing microfilaricidal efficacy but only serves as an indirect indicator of macrofilaricidal activity. We assessed circulating nucleic acids from Onchocerca volvulus as an alternative to skin snips. We screened a plasma sample set of infected individuals followed up at four, 12 and 21 months after microfilaricidal (ivermectin, n = four), macrofilaricidal (doxycycline, n = nine), or combination treatment (n = five). Two parasite-derived miRNAs, cel-miR-71-5p and bma-lin-4, and O-150 repeat DNA were assessed. Highly abundant DNA repeat families identified in the O. volvulus genome were also evaluated. miRNAs were detected in two of 72 plasma samples (2.8%) and two of 47 samples (4.3%) with microfilaridermia using RT-qPCR. O-150 DNA was detected in eight (44.4%) baseline samples by qPCR and the number of positives declined post-treatment. One doxycycline-treated individual remained O-150 positive. However, only 11 (23.4%) samples with microfilaridermia were qPCR-positive. Analysis by qPCR showed novel DNA repeat families were comparatively less abundant than the O-150 repeat. Circulating parasite-derived nucleic acids are therefore insufficient as diagnostic tools or as biomarkers of treatment efficacy for O. volvulus. Onchocerciasis, or "river blindness" is a parasitic disease caused by the filarial worm Onchocerca volvulus. Over 100 million people are at risk of infection, of which 99% reside in 31 sub-Saharan African countries endemic for onchocerciasis 1,2. In Africa, the standard elimination strategy consists of annual mass drug administration (MDA) with ivermectin (Mectizan; IVM). IVM kills microfilariae (mf) in the skin and is used in MDA programmes, which aim to reduce disease burden and block transmission to black fly vectors (Simulium spp.) 3. A specific and sensitive diagnostic test is needed for onchocerciasis 'end-game' scenarios, both to verify elimination and to detect cases when endemicity levels no longer justify MDA 4. High sensitivity is required for O. volvulus hypoendemic areas to detect low mf densities, as well as occult and amicrofilaridermic infections, and to monitor infection recrudescence 5. High specificity is also required to discriminate between closely related filarial nematodes with overlapping geographic distributions. This is particularly relevant in areas co-endemic for O. volvulus and the filarial worm Loa loa, such as in "hypoendemic hotspots" 6 , where IVM treatment can cause serious adverse events (SAEs) when L. loa microfilaraemia is high (>30,000 mf/ml) 7. In these areas, alternative strategies with drugs that are safe to use with loiasis will be required to meet elimination targets 8. Alternative 'test and (not) treat' (TaNT) approaches, Loa-first and Oncho-first, can be used to identify and exclude people at risk of SAEs or those not infected with onchocerciasis 9. While the new rapid Loa...