A Cyclical Feeding Model for Pathogen Transmission and Its Application to Determine Vectorial Capacity from Vector Infection Rates

Area effects of bednet use in a malaria-endemic area in Papua New Guinea

“…Faced with a bednet, a hostseeking mosquito can only complete the gonotrophic cvcle if it finds its way both in and out of the net or finds aitemative unprotecied hosts. Mosquito fatigue or death at any point in this process reduces the sporozoite rate in proportion to the effect on vector survival (SAUL et al, 1990), In the longer term, effects of UTNs on transmission may be greater than the short-term effect on sporozoite rates, irrespective ofwhether this effect results from reduced gametocytaemia, diversion on to animal hosts, reduced mosquito survival, or all these combined, as appears likely in Wosera. This is because reduction in sporozoite rates causes decreased prevalence in humans and hence further reductions in mosquito infection via a positive feedback loop.…”

Olfaction in vector-host interactions

“…Saul (2003) developed two deterministic models, one for stable transmission and one for epidemic situations. They were based on the cyclic feeding model he and his colleagues had previously developed (Saul et al 1990) rather than the a continuous feeding model refined from Ross' model by Macdonald (1957). Saul's model assumed that mosquitoes will not feed for a few days after becoming engorged; whilst the respective gonotrophic cycle is completed (cyclical feeding).…”

Survival and infection probabilities of anthropophagic anophelines from an area of high prevalence of Plasmodium falciparum in humans

“…These estimates do not depend on either the assumption of an exponential survival distribution or on knowledge of the duration of the oviposition cycle. Similarly, equation (21) of Saul et al (1990) using the estimated proportion infectious, S, and the delayed oocyst rates was also used to obtain estimates, P £ ., and P E ,,, of survival per extrinsic cycle.…”

“…The analogous formula, relating the sporozoite rate S to the probability of surviving the extrinsic cycle, provides a further of estimates of K, KEJ, KE X , and K.M. Saul et al (1990) suggested the use of estimates of survival per feeding cycle rather than survival per day in determinations of the infectious reservoir and Burkot et al (1990) provided an extension to this using immediate infection rates. They derived formulae for the infectious reservoir valid for a more general system including outdoor resting and zoophagy.…”

“…Since anophelines are gonotrophically concordant after the first cycle, the feeding cycle is equivalent to the oviposition cycle and M can be used directly as an estimate of the survival per feeding cycle (Clements & Paterson, 1981). Saul et al, (1990) and Burkot el al. (1990) have also shown that estimates of survival per feeding cycle can be made by comparing immediate infection (oocyst) rates with delayed rates determined in mosquitoes kept for a holding period of five days.…”