HIV incidence and prevalence among adults aged 15-64 years in Rwanda: Results from the Rwanda Population-based HIV Impact Assessment (RPHIA) and District-level Modeling, 2019

Objectives The 2018–19 Rwanda Population-based HIV Impact Assessment (RPHIA) was conducted to measure national HIV incidence and prevalence. District-level estimates were modeled to inform resources allocation. Methods RPHIA was a nationally representative cross-sectional household survey. Consenting adults were interviewed and tested for HIV using the national diagnostic algorithm followed by laboratory-based confirmation of HIV status, and testing for viral load (VL), limiting antigen (LAg) avidity and presence of antiretrovirals. Incidence was calculated using normalized optical density ≤ 1•5, VL ≥ 1,000 copies/mL, and undetectable antiretrovirals. Survey and programmatic data were used to model district-level HIV incidence and prevalence. Results Of 31,028 eligible adults, 98•7% participated in RPHIA and 934 tested HIV positive. HIV prevalence among adults in Rwanda was 3•0% (95% CI:2•7–3•3). National HIV incidence was 0•08% (95% CI:0•02–0•14) and 0•11% (95% CI:0•00–0•26) in the City of Kigali (CoK). Based on district-level modeling, HIV incidence was greatest in the three CoK districts (0•11% to 0•15%) and varied across other districts (0•03% to 0•10%). Conclusions HIV prevalence among adults in Rwanda is 3.0%; HIV incidence is low at 0.08%. District-level modeling has identified disproportionately affected urban hotspots: areas to focus resources

Trypsin-Like Serine Proteases in Lutzomyia longipalpis – Expression, Activity and Possible Modulation by Leishmania infantum chagasi

Background: Midgut enzymatic activity is one of the obstacles that Leishmania must surpass to succeed in establishing infection. Trypsins are abundant digestive enzymes in most insects. We have previously described two trypsin cDNAs of L. longipalpis: one (Lltryp1) with a bloodmeal induced transcription pattern, the other (Lltryp2) with a constitutive transcription pattern. We have now characterized the expression and activity of trypsin-like proteases of Lutzomyia longipalpis, the main vector of visceral leishmaniasis in Brazil. Methodology and Principal Findings: In order to study trypsin expression profiles we produced antibodies against peptides specific for Lltryp1 and Lltryp2. The anti-Lltryp1-peptide antibody revealed a band of 28 kDa between 6 and 48 hours. The anti-Lltryp2 peptide antibody did not evidence any band. When proteinaceous substrates (gelatin, hemoglobin, casein or albumin) were co-polymerized in polyacrylamide gels, insect midguts obtained at 12 hours after feeding showed a unique proteolytic pattern for each substrate. All activity bands were strongly inhibited by TLCK, benzamidine and 4-amino-benzamidine, indicating that they are trypsin-like proteases. The trypsin-like activity was also measured in vitro at different time points after ingestion of blood or blood containing Leishmania infantum chagasi, using the chromogenic substrate BArNA. L. longipalpis females fed on blood infected with L. i. chagasi had lower levels of trypsin activity after 12 and 48 hours than non-infected insects, suggesting that the parasite may have a role in this modulation. Conclusions and Significance: Trypsins are important and abundant digestive enzymes in L. longipalpis. Protein production and enzymatic activity followed previously identified gene expression of a blood modulated trypsin gene. A decrease of enzymatic activity upon the parasite infection, previously detected mostly in Old World vectors, was detected for the first time in the natural vector-parasite pair L. longipalpis-L. i. chagasi