Costs and benefits of vertical and horizontal transmission of dengue virus.
Parasites can be transmitted vertically and/or horizontally, but the costs or benefits for the host of infection have only been tested after horizontal transmission. Here, we report for the first time, to our knowledge, the survival, reproduction and infection of Aedes aegypti during vertical and horizontal transmission of dengue virus 2 (DENV-2). Females infected horizontally produced more eggs, with a sex ratio skewed towards males, compared with uninfected controls. However, there was no significant difference in the number of emerging adults or in survival of mothers. In contrast, dengue-infected female offspring (vertical transmission) had a shorter lifespan but there were no significant differences in the number of eggs or sex ratio, compared with controls. Finally, the corroboration of infection revealed that virus infected about 11.5% and 8.8% of pools of mothers and of daughters, respectively. These results suggest that the mode of infection and the contact with the virus has no reproductive costs to female mosquitoes, which may explain why both types of transmission are evolutionarily maintained. In addition, we suggest that more attention should be paid to the male contribution to virus dissemination within and among populations and as reservoirs of the infection for human diseases.
Departamento de Arbovirus, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Av. Universidad 655, Cuernavaca, Morelos C. P. 62508, México.|Escuela Nacional de Estudios Superiores, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda San José de la Huerta, Morelia, Michoacán 58190, México.
Gloria
G
Ruiz-Guzmán
Departamento de Arbovirus, Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Av. Universidad 655, Cuernavaca, Morelos C. P. 62508, México.
José
J
Ramos-Castañeda
Departamento de Estadística, Universidad Autónoma de Aguascalientes, Av. Universidad No. 940, Ciudad Universitaria, Aguascalientes, Ags 20131, México.
Angélica
A
Hernández-Quintero
Escuela Nacional de Estudios Superiores, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda San José de la Huerta, Morelia, Michoacán 58190, México jcg@enesmorelia.unam.mx.
Jorge
0000-0002-9231-0641
J
Contreras-Garduño
D000330:Aedes / Q000821:virology; D000818:Animals; D003715:Dengue / Q000635:transmission*; D003716:Dengue Virus / Q000502:physiology*; D018562:Disease Transmission, Infectious; D005260:Female; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D010063:Ovum / Q000502:physiology; D011817:Rabbits; D012744:Sex Ratio; D016019:Survival Analysis
Aedes aegypti; Evolutionary parasitology; Host–parasite relationship; Life-history traits; Mutualism; Parasitism