Effect of the Aedes fluviatilis saliva on the development of Plasmodium gallinaceum infection in Gallus (gallus) domesticus

Abstract

Effect of Aedes fluviatilis saliva on the development of Plasmodium gallinaceum experimental infection inSaliva components from haematophagous arthropods may modulate the host immune system and would represent an adaptation to evolution related with the blood feeding behavior (Ribeiro et al. 1984, Ribeiro 1987, 1989, James & Rossignol 1991. Several substances in saliva from different vectors such as ticks, phlebotomine, and mosquitoes prevent host homeostasis at the bite site during the blood ingestion. Such components may show different activities such as anti-homeostatic, vasodilator, anti-inflammatory, immune-suppressor, and many others (review in Kamhawi et al. 2000).The effect of saliva substances on the pathogen infectivity to vertebrates was firstly demonstrated by Titus and Ribeiro (1988) in phlebotomine followed by Junes and collaborators (1993) in ticks. Nowadays, the importance of saliva for blood feeding and pathogen infections has been extensively analyzed in several arthropod vectors (review in Gillespie et al. 2000). Therefore, there are few studies about the effect of mosquito saliva on infectivity of Plasmodium parasites. Early studies showed some protection against infection by P. berghei sporozoites when mice were previously immunized with mosquito salivary gland homogenate (Alger et al. 1972, Alger & Harant 1976). In addition, Vaughan et al. (1999) suggested that saliva was one of the factors that could contribute to a more efficient rodent infection when the parasites were injected by mosquito vector bites. In the current study, we evaluate the role of Aedes fluviatilis saliva in the experimental infections of chicken Gallus (gallus) domesticus with P. gallinaceum, the causative agent of avian malaria and its immunogenic potential to control parasitemia. MATERIALS AND METHODSMosquitoes -Ae. fluviatilis were obtained from a colony established and kept in the Laboratory of Medical Entomology, Centro de Pesquisas René Rachou-Fiocruz in the state of Minas Gerais. The mosquitoes were kept in an acclimated insectary with average temperature between 26-28 o C and relative air humidity around 70-80%, in a cycle of 12 h in the dark and 12 h in the light (Consoli & Williams 1978). The mosquitoes were provided with 10% glucose solution and water until the time of the experiments.Mosquito infection -Groups of 4 to 6 day-old female mosquitoes were allowed to feed on the skin of P. gallinaceum infected chickens (parasitaemia levels ranging from 3.5 to 10%). The infection evaluation was carried out 7 to 9 days after the infective blood meal by the presence of ookinetes in dissected midguts, which were dissected in PBS (phosphate buffer solution) and stained with 2% mercury chrome in order to visualize the parasites. The percentage of infected mosquitoes and the number of ookinetes per midgut were recorded through optical microscopic examination. All mosquitoes used to infect chickens were also previously examined for the presence of sporozoites 14 days after the infection (Ozaki et al.1984).Chickens -New...

Uninfected Mosquito Bites Confer Protection against Infection with Malaria Parasites

“…One original study investigating irradiated sporozoites as vaccine components used repeated vaccination with large amounts of mosquito salivary gland homogenate (SGH; 70 glands) as a control and demonstrated that this procedure confers partial protection to Plasmodium berghei infection in mice (1,2). More recently, it has been demonstrated that Plasmodium gallinaceum parasitemia levels are increased in the presence of Aedes fluviatilis saliva in a chicken malaria model, a response that was reversed with prior exposure to mosquito saliva (43).…”

Plasmodium yoelii sporozoites modulate cytokine profile and induce apoptosis in murine Kupffer cells

“…We attribute, at least partially, the finding that SG extract induced the secretion of pro-inflammatory cytokines in vitro to these bacterial contaminants. The effect of mosquito-derived contaminants may be important, because injection of uninfected SG extract induced a high degree of protection against challenge with P. berghei sporozoites or Plasmodium gallinaceum -infected mosquito bites (Alger et al, 1972; Rocha et al, 2004). While this protective effect may be beneficial when induction of an immune response is desired, elimination of microbial contamination, for instance by breeding and maintaining mosquitoes under sterile conditions (Luke and Hoffman, 2003), may be necessary to achieve optimal liver infection rates for biological studies.…”

West Nile Virus: Biology, Transmission, and Human Infection

“…Saliva from hematophagous insects has been shown to alter the transmissibility of many pathogens (1,50,160,178,187,206,223,231). Saliva from both A. aegypti and C. tarsalis has been shown to alter transmissibility in a WNV mouse model (189,206).…”