DOI: 10.5061/dryad.n02v6wx3n
title: Mosquito aging modulates the development, virulence and transmission potential of pathogens

description: Host age variation is a striking source of heterogeneity that can shape
 the evolution and transmission dynamic of pathogens. Compared to
 vertebrate systems, our understanding of the impact of host age on
 invertebrate-pathogen interactions remains limited. We examined the
 influence of mosquito age on key life-history traits driving human malaria
 transmission. Females of Anopheles coluzzii, a major malaria vector,
 belonging to three age classes (4, 8, and 12 day-old), were experimentally
 infected with Plasmodium falciparum field isolates. Our findings revealed
 reduced competence in 12-day-old mosquitoes, characterized by lower
 oocyst/sporozoite rates and intensities compared to younger mosquitoes.
 Despite shorter median longevities in older age classes, infected
 12-day-old mosquitoes exhibited improved survival, suggesting that the
 infection might act as a fountain of youth for older mosquitoes
 specifically. The timing of sporozoite appearance in the salivary glands
 remained consistent across mosquito age classes, with an extrinsic
 incubation period of approximately 13 days. Integrating these results into
 an epidemiological model revealed a lower vectorial capacity for older
 mosquitoes compared to younger ones, albeit still substantial due to
 extended longevity in the presence of infection. Considering age
 heterogeneity provides valuable insights for ecological and
 epidemiological studies, informing targeted control strategies to mitigate
 pathogen transmission.
description: # Mosquito aging modulates the development, virulence and transmission
 potential of pathogens
 [https://doi.org/10.5061/dryad.n02v6wx3n](https://doi.org/10.5061/dryad.n02v6wx3n) 5 datasets + 1 R script corresponding to the statistical analysis of the data and the modeling of vectorial capacity # Description of the data and file structure Analysis of the effect of age on oocyst prevalence and intensity in An. coluzzii "fig2_oocyst_data.txt" has 4 columns: * mosquito_id : a unique code for each dissected mosquito (n= 605) * age_class : a 3-level categorical variable corresponding to each of the three age group (12, 8 and 4-day-old) * isolate : a 4-level categorical variable corresponding to each of the four gametocyte carriers (replicates) * oocyst : number of developed oocyst in each mosquito midgut Analysis of the effect of age on sporozoite prevalence and intensity in An. coluzzii "fig2_sporozoite_data.txt" has 5 columns: * mosquito_id : a unique code for each dissected mosquito (n= 729) * age_class : a 3-level categorical variable corresponding to each of the three age group (12, 8 and 4-day-old) * isolate : a 4-level categorical variable corresponding to each of the four gametocyte carriers (replicates) * Ct : number of cycle during the qPCR (this is a proxy of the quantity of parasite DNA in salivary glands) * NB: this variable includes NA values which mean that no amplification occured and hence that the sample is negative * positive: a binary variable corresponding to the infection status of mosquitoes (1: presence of, 0: absence of sporozoite) Analysis of the effect of age and infection on mosquito survival "fig3_survival_data.txt" has 8 columns: * mosquito_id : a unique code for each tracked mosquito (n= 657) * cup: a code for each paper cup containing mosquitoes (n=48 cups of ~15 mosquitoes (range = 4-18)) * The naming convention for each cup follows a structured pattern: the first two letters represent one of * the three age groups (G1, G2, or G3), the third letter indicates the ID of the parasite isolate (A to D), * the fourth and fifth letters signify whether the mosquitoes were exposed (yes) or not (no) to the infectious blood meal, * and the final letter specifies the cup number (1 or 2) for each group, isolate, exposure status. * age_class : a 3-level categorical variable corresponding to each of the three age group (12, 8 and 4-day-old) * isolate : a 4-level categorical variable corresponding to each of the four gametocyte carriers (replicates) * exposure : a two-level categorical variable corresponding to whether mosquitoes received an infectious (yes) or uninfectious blood-meal (no) * infection_status: a 3-level categorical variable corresponding to whether mosquitoes were uninfected controls, became infected upon exposure or remained uninfected upon exposure * daysPI: the day (time post-infection) of mosquito death * censor: censoring indicator (1 indicates that the response is a time at death, 0 indicates that the individual was alive when last seen). because all mosquitoes were followed until death, this indicator is 1 for every mosquito Analysis of the effect of age on the parasite's EIP "fig4_EIP_data.txt" has 7 columns: * mosquito_id : a unique code for each dissected mosquito (n= 802) * age_class : a 2-level categorical variable corresponding to each of the two age group (12 and 4-day-old) * isolate : a 3-level categorical variable corresponding to each of the three gametocyte carriers (replicates) * dpi : day (time post-infection) at which mosquitoes were dissected * oocyst : number of developed oocyst in each mosquito midgut * broken_oocyst: number of ruptured oocysts (NB: there are some NA values for dpi 6 because broken oocysts are unlikely * to occur at this timepoint and were therefore not recorded) * spz: a binomial variable corresponding to the presence (1) or absence (0) of sporozoite in mosquito salivary glands * (NB: there are some NA values for dpi 6 because sporozoites are unlikely to occur at this timepoint and were therefore not recorded. A few additional NA are observed beyond dpi 6 when mosquito salivary glands were lost during the dissection) Analysis of the effect of age on vectorial capacity "fig5_vectorial_capacity_data.txt" has 3 columns: * scenario : a 3-level categorical variable corresponding to each scenario * age_class : a 2-level categorical variable corresponding to each of the two age group (12 and 4-day-old) * vectorial_capacity: the response variable simulated from the mathematical model # Code/Software 1 R script "Rscript_mosquito_age_infection" corresponding to the analysis of the 5 data set presented above.