Effects of Temperature on the Development of Dirofilaria immitis (Leidy) in Anopheles quadrimaculatus Say1 and on Vector Mortality Resulting from this Development2,3

Vectorial competence of Aedes aegypti (Linnaeus 1762) Rio de Janeiro Strain, to Dirofilaria immitis (Leidy 1856)

“…aegypti were used (Taylor 1960, Buxton & Mullen 1981. Although larvae development speed is highly dependent on temperature (Kutz & Dobson 1974, Christensen & Hollander 1978, some differences may have occurred among protocols, even though all studies reported the same laboratory conditions, including temperature. The development of the parasite can also vary within mosquito species (Frimeth & Arai 1983) and therefore the genetic diversity of different strains of the same species could be the cause of such variation.…”

“…The mortality rate for infected mosquitoes is higher than for uninfected mosquitoes and is probably caused by two factors: (1) the invasion of the Malpighian tubule cells by the microfilarial stage and (2) the escape of the infective larvae from the Malpighian tubules and their subsequent movement to the head and mouthparts via the hemocoel (Kutz & Dobson 1974). It is known that when the filariae burden in the Malpighian tubules increases, the result is excessive mortality that may approach 100% (Kershaw et al 1953, Webber & Hawking 1955, Christensen 1978.…”

Potential Vectors of Dirofilaria immitis (Leidy, 1856) in Itacoatiara, Oceanic Region of Niterói Municipality, State of Rio de Janeiro, Brazil

“…Environmental temperature directly influences the rate of larval development in the mosquito (Kutz & Dobson 1974, Christensen & Hollander 1978 so, transmission potential can change seasonally with temperature. Different species of mosquitoes were infective during different months: Ae.…”

“…Intrinsic barriers to D. immitis development in mosquitoes include: larval damage due to the cibarial armature (Coluzzi & Trabucchi 1968) or to the presence of oxyhaemoglobin crystals formed by bloodmeal coagulation in the midgut (Nayar & Sauerman 1975, Lowrie 1991; trapping of larvae in the coagulated bloodmeal in the mosquito's midgut (Kartman 1953); lysis of larval cuticle by host cells (Talluri & Cancrini 1994) and other immune responses, i.e., encapsulation and/or melanization of the parasite in the mosquito Malpighian tubules (Lindemann 1977, Christensen 1981, Christensen et al 1989. Among extrinsic factors, temperature is the most important and has been shown to regulate the duration of parasite development in the mosquito (Kutz & Dobson 1974, Christensen & Hollander 1978.…”

Vector competence of Culex quinquefasciatus Say, 1823 exposed to different densities of microfilariae of Dirofilaria immitis (Leidy, 1856)

“…It is also known that infected mosquitoes are more sensitive to temperature variations, with diminishing survival rates at higher temperatures (Kutz & Dobson 1974). However, the main cause of mortality of infected females is attributed to the development of D. immitis in the mosquito, with peak mortality generally occurring within the first 48 hours after infection, when first stage larvae (L 1 ) of the nematode invade the Malpighian tubules of the females and later, between the 12 th and 14 th day, break free from these tubules and migrate to the head and proboscis of the culicids (Kartman 1953;Buxton & Mullen 1981).…”