Studies on the Effect of Various Factors on the Infection Rate of<i>Anopheles Elutus</i>with Different Species of<i>Plasmodium</i>

Kligler, I. J.; Mer, G.

doi:10.1080/00034983.1937.11684967

Cited by 15 publications

(6 citation statements)

References 1 publication

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“…Life tables showed clearly that mortality during gametogenesis and fertilization ( i.e ., k-1 ) was generally the most critical transition determining an infection outcome (Table 3 ). Importantly, differences among volunteers in gametocyte and trophozoite densities, gametocyte sex ratios and blood haematocrits did not correlate with differences in volunteer infectiousness – an observation noted previously by other workers [ 36 - 38 ]. Obviously, something else influenced the early developmental success rates of different gametocyte populations.…”

Section: Discussionsupporting

confidence: 56%

Population dynamics of sporogony for Plasmodium vivax parasites from western Thailand developing within three species of colonized Anopheles mosquitoes

Zollner

Ponsa

Garman

et al. 2006

Malar J

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BackgroundThe population dynamics of Plasmodium sporogony within mosquitoes consists of an early phase where parasite abundance decreases during the transition from gametocyte to oocyst, an intermediate phase where parasite abundance remains static as oocysts, and a later phase where parasite abundance increases during the release of progeny sporozoites from oocysts. Sporogonic development is complete when sporozoites invade the mosquito salivary glands. The dynamics and efficiency of this developmental sequence were determined in laboratory strains of Anopheles dirus, Anopheles minimus and Anopheles sawadwongporni mosquitoes for Plasmodium vivax parasites circulating naturally in western Thailand.MethodsMosquitoes were fed blood from 20 symptomatic Thai adults via membrane feeders. Absolute densities were estimated for macrogametocytes, round stages (= female gametes/zygotes), ookinetes, oocysts, haemolymph sporozoites and salivary gland sporozoites. From these census data, five aspects of population dynamics were analysed; 1) changes in life-stage prevalence during early sporogony, 2) kinetics of life-stage formation, 3) efficiency of life-stage transitions, 4) density relationships between successive life-stages, and 5) parasite aggregation patterns.ResultsThere was no difference among the three mosquito species tested in total losses incurred by P. vivax populations during early sporogony. Averaged across all infections, parasite populations incurred a 68-fold loss in abundance, with losses of ca. 19-fold, 2-fold and 2-fold at the first (= gametogenesis/fertilization), second (= round stage transformation), and third (= ookinete migration) life-stage transitions, respectively. However, total losses varied widely among infections, ranging from 6-fold to over 2,000-fold loss. Losses during gametogenesis/fertilization accounted for most of this variability, indicating that gametocytes originating from some volunteers were more fertile than those from other volunteers. Although reasons for such variability were not determined, gametocyte fertility was not correlated with blood haematocrit, asexual parasitaemia, gametocyte density or gametocyte sex ratio. Round stages and ookinetes were present in mosquito midguts for up to 48 hours and development was asynchronous. Parasite losses during fertilization and round stage differentiation were more influenced by factors intrinsic to the parasite and/or factors in the blood, whereas ookinete losses were more strongly influenced by mosquito factors. Oocysts released sporozoites on days 12 to 14, but even by day 22 many oocysts were still present on the midgut. The per capita production was estimated to be approximately 500 sporozoites per oocyst and approximately 75% of the sporozoites released into the haemocoel successfully invaded the salivary glands.ConclusionThe major developmental bottleneck in early sporogony occurred during the transition from macrogametocyte to round stage. Sporozoite invasion into the salivary glands was very efficient. Information on the natur...

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Section: Discussionsupporting

confidence: 56%

Population dynamics of sporogony for Plasmodium vivax parasites from western Thailand developing within three species of colonized Anopheles mosquitoes

Zollner

Ponsa

Garman

et al. 2006

Malar J

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“…The temperature drop during gametocyte entry into the mosquito may signal the gametogenesis (Kliger "& Mer, 1937). In vitro a 5 °C drop from 37 °C is sufficient to trigger the phenomenon (Sinden & Croll, 1975;Sinden, 19836;Ogwan'g et al 1993).…”

Section: Development Of Plasmodium Ookinetesmentioning

confidence: 99%

Plasmodiumookinete development in the mosquito midgut: a case of reciprocal manipulation

Shahabuddin

1998

Parasitology

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The ookinete is one of the most important stages of Plasmodium development in the mosquito. It is morphologically and biochemically distinct from the earlier sexual stages--gametocytes and zygote, and from the later stages--oocyst and sporozoites. Development to ookinete allows the parasite to escape from the tightly packed blood bolus, to cross the sturdy peritrophic matrix (PM), to be protected from the digestive environment of the midgut lumen, and to invade the gut epithelium. The success of each of these activities may depend on the degree of the biochemical and physical barriers in the mosquito (such as density of blood bolus, thickness of peritrophic matrix, proteolytic activities in the gut lumen etc.) and the ability of the ookinete to overcome these barriers. Ookinete motility, secretion of chitinase, resistance to the digestive enzymes, and recognition/invasion of the midgut epithelium all may play crucial roles in the transformation to oocyst. The overall sporogonic development of Plasmodium, therefore, depends on the results of the two-way manipulations between the parasite and the vector mosquito. Study of ookinete development and of the cellular and biochemical complexities of the mosquito gut may therefore lead to the design of novel strategies to block the transmission of malaria. This article reviews the intricate interactions between the parasite and the mosquito midgut in the context of development and transmission of Plasmodium parasites.

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“…Physiological studies of exflagellation have included those which examined thermal dependence (Claus, 1903;Kliger & Mer, 1937;Bishop & McConnachie, 1956;Bano, 1958); the effects of changes in pH and CO 2 tension (Marchoux & Chorine, 1932;Chorine, 1933;Bishop & McConnachie, 1956); and the influence of plasma factors (Bishop & McConnachie, 1956). The effect of the mosquito gut on the production of zygotes has been examined by Yoeli & Upmanis (1968) and Ball & Chao (1960).…”

Section: Intkoductiosmentioning

confidence: 99%

Cytology and Kinetics of microgametogenesis and fertilization in Plasmodium yoelii nigeriensis

Sinden

Croll

1975

Parasitology

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The sexual development of the microgametocyte of Plasmodium yoelii nigeriensis may be subdivided into microgametogenesis which includes exflagellation, dispersal of the gametes and fertilization. Under our experimental conditions microgametogenesis takes about 8–15 min at 20 °C, the duration of this period being inversely related to temperature. Exflagellation takes less than 1 min, subsequent dispersal of gametes may continue for 40 min. We find that exflagellation is totally inhibited in vitro by temperatures of 30 °C and above, and by certain invertebrate tissue culture media. Exflagellation may occur within a persistent host cell plasmalemma, which seriously impedes the escape of the 8 microgametes. Microgametes move by sinusoidal or helical waves which may be rapid (10 waves/s), slow (< 1 wave/s) or they may be immobile. Microgamete activity, which is alternately rapid/slow or slow/immobile, declines linearly with time. Fertilization which takes less than 1 min results from characteristic behavioural changes by the microgamete; vibratory waves are responsible for the penetration of the macrogamete by the microgamete. The microgamete completely enters the macrogamete and therein continues its cyclical activity.

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Studies on the Effect of Various Factors on the Infection Rate ofAnopheles Elutuswith Different Species ofPlasmodium

Cited by 15 publications

References 1 publication

Population dynamics of sporogony for Plasmodium vivax parasites from western Thailand developing within three species of colonized Anopheles mosquitoes

Population dynamics of sporogony for Plasmodium vivax parasites from western Thailand developing within three species of colonized Anopheles mosquitoes

Plasmodiumookinete development in the mosquito midgut: a case of reciprocal manipulation

Cytology and Kinetics of microgametogenesis and fertilization in Plasmodium yoelii nigeriensis

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