Comparative studies on sibling species of the Anopheles gambiae Giles complex (Dipt., Culicidae): bionomics and vectorial activity of species A and species B at Segera, Tanzania

1972 ◽  
Vol 62 (2) ◽  
pp. 295-317 ◽  
Author(s):  
G. B. White ◽  
S. A. Magayuka ◽  
P. F. L. Boreham
Keyword(s):  
Survival Rate ◽  
Anopheles Gambiae ◽  
Sibling Species ◽  
Malaria Vectors ◽  
Daily Survival Rate ◽  
Filarial Infection ◽  
Blood Indices ◽  
Biting Rate ◽  
Short Rains ◽  
Anopheles Gambiae Giles

Collections of Anopheles gambiae Giles complex, A. funestus Giles group and other mosquitoes were made by spray-catch from twelve catching stations indoors and by hand-catch from pit shelters at two catching stations at Segera, Tanzania, between January 1970 and June 1971. Females of A. gambiae were identified cytotaxonomically as sibling species A or B of the complex. In houses during 1970, A. gambiae species B was more numerous at first than A, but A became predominant during the long rains of March-May. In the cool dry weather of June-November both A and B densities declined and the A:B ratio surpassed 50:1. The short rains in December produced a population explosion of species B and less multiplication of species A, the B:A ratio reaching >11:1. In 1971, hot dry weather during January-March caused declines of species A and B with a maximum B: A ratio of 13:1. Long rains, coming in late March, provoked a resurgence of A and a concurrent decline of B, so that the A:B ratio again reached 20:1 in June. Similar cycles of species A and B were observed outdoors, although the relative numbers outdoors/indoors averaged 2·3 times more for species B than for species A. In A. funestus, A. gambiae species A and A. gambiae species B Human Blood Indices were 97·5%, 91·2% and 60·9% indoors and 24%, 2% and 7% outdoors, respectively. Respective malaria sporozoite rates were 1·62%, 4·23% and 0·32% and minimum rates of stage-Ill filarial infection were 0·33%, 0·44% and 0·57%. Sporozoite-positive and sporozoite-negative mosquitoes exhibited similar HBF's in species A and discrepant HBI's in species B. The HBI's were higher in filariapositive A and B females than in filaria-negative females. Gregarines occurred in 1·36% of species A and 0·38% of species B. Trematode cysts were seen in two specimens of species A.Of A and B females 28% and 4%, respectively, had four-banded palps. It is shown mathematically that the discrepant malaria sporozoite rates in species A and B may be explained by extrapolating from the man-biting rate and probable daily survival rate for each species. This implies that no unrecognised factors play a major role in causing the contrasting efficiency of these two sibling species as malaria vectors.

scholarly journals Human biting rhythm of Anopheles gambiae Giles, 1902 (Diptera: Culicidae) and sleeping behaviour of pregnant women in a lagoon area in Southern Benin

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Armel Djènontin ◽  
Aziz Bouraima ◽  
Christophe Soares ◽  
Seun Egbinola ◽  
Gilles Cottrell
Keyword(s):  
Plasmodium Falciparum ◽  
Pregnant Women ◽  
Anopheles Gambiae ◽  
Early Morning ◽  
Allelic Frequency ◽  
Malaria Vectors ◽  
Mosquito Nets ◽  
Anopheles Gambiae Giles ◽  
Almost All ◽  
Southern Benin

Abstract Objective In the framework of EVALMOUS study aiming to assess the use and effectiveness of mosquito nets by pregnant women and other members of their household in a lagoon area in southern Benin, the behaviour of pregnant women relative to the time they go to bed using the net were recorded. Malaria vectors biting rhythm, Plasmodium falciparum infection and insecticide resistance genes in malaria vectors were also determined. Results Overall, 3848 females of Anopheles gambiae s. l were collected and 280 pregnant women responded to the survey. Almost all Anopheles gambiae s. l. tested were Anopheles coluzzi Coetzee and Wilkerson 2013 (Diptera: Culicidae). The CSP index in malaria vector was 1.85% and the allelic frequency of kdr gene was 74.4%. Around 90% of bites and Plasmodium falciparum Welch, 1897 (Haemosporida: Plasmodiidae) transmission occurred between 10 p.m. and 6 a.m., which coincides with the period when more than 80% of pregnant women were under bednet. Despite a slight early evening and early morning biting activity of malaria vectors in the study area, the good use of nets might remain a useful protection tool against mosquito biting and malaria transmission.

Comparative studies on sibling species of the Anopheles gambiae Giles complex (Dipt., Culicidae). III. The distribution, ecology, behaviour and vectorial importance of species D in Bwamba County, Uganda, with an analysis of biological, ecological, morphological and cytogenetical relationships of Ugandan species D

1973 ◽  
Vol 63 (1) ◽  
pp. 65-97 ◽  
Author(s):  
G. B. White
Keyword(s):  
Anopheles Gambiae ◽  
Sibling Species ◽  
Comparative Studies ◽  
Hot Springs ◽  
Limited Range ◽  
Brackish Marsh ◽  
Complex Species ◽  
Human Malaria ◽  
Chromosomal Inversions ◽  
Anopheles Gambiae Giles

AbstractStudies on mosquitoes of the Anopheles gambiae Giles complex at Bwamba, Uganda, showed that the newly recognized sibling species D may be restricted to breeding areas where waters contain unusual solutes, the effluent from hot springs at Buranga being particularly favourable. Two other members of the complex, species A and B, were also detected in the neighbourhood apparently breeding only in more normal situations. Species D specimens were usually identified cytotaxonomically, from the presence of XR potytene chromosomes of the type also occurring in species C and A. melas (Theo.) (neither of which is known from the area). Most species D females have distinctively pale palps, a valuable although limited distinguishing feature. Features of setation on larvae and pupae were discerned which might serve usefully as meristic chaetotaxonomic factors, at least locally, if tested further. Although it is unquestionable that a large proportion of species D females forage in the Semliki forest, feeding on primates, bovids, suids or unsuspected hosts, it was demonstrated that many species D females are markedly anthropophilic and display strong endophilic and endophagic tendencies, to the extent that they may be primary vectors of human malaria and filariasis over a limited range. Species D males were rare indoors and remained mainly within the forest, where great numbers rest low on vegetation in company with unfed females, near to breeding areas of brackish marsh. Two polymorphic chromosomal inversions in species D apparently embody the genetical causes of its differentiation. Cytogenetical evidence indicates that species D is phylogenetically nearly intermediate between A. melas and species C of the A. gambiae complex.

Studies on the sibling species Anopheles gambiae Giles and Anopheles arabiensis Patton (Diptera: Culicidae) in the Kisumu area, Kenya.

1979 ◽  
Vol 69 (1) ◽  
pp. 43-53 ◽  
Author(s):  
R. B. Highton ◽  
Joan H. Bryan ◽  
P. F. L. Boreham ◽  
J. A Chandler
Keyword(s):  
Anopheles Gambiae ◽  
Sibling Species ◽  
Malaria Infection ◽  
Anopheles Arabiensis ◽  
Dominant Species ◽  
Feeding Habits ◽  
Seasonal Abundance ◽  
Infection Rates ◽  
Sporozoite Rate ◽  
Anopheles Gambiae Giles

AbstractA study was undertaken of the seasonal abundance, feeding habits, resting habits and malaria infection rates of the sibling species Anopheles gambiae Giles and A. arabiensis Patton on the Kano Plain, Kenya, and the surrounding foothills. A. arabiensis was the dominant species on the plains and A. gambiae in the foothills. A. gambiae was highly anthropophilic with 92% feeding on man, whereas 59% of A. arabiensis fed on cattle. In both species, the choice of host was affected by the availability of cattle. A. arabiensis rested out of doors more commonly than A. gambiae. The sporozoite rate in A. gambiae was 5·33%, 15·98 times higher than the rate of 0·33% found in A. arabiensis.

scholarly journals Sporozoite Infection Rate and Identification of the Infective and Refractory Species of Anopheles gambiae (Giles) Complex

2014 ◽  
Vol 6 (4) ◽  
pp. 407-413
Author(s):  
Music Temitope OBEMBE ◽  
Idowu J. AWOPETU
Keyword(s):  
Anopheles Gambiae ◽  
Infection Rate ◽  
Sibling Species ◽  
Sensu Stricto ◽  
Malaria Vectors ◽  
Southwestern Nigeria ◽  
Complex Span ◽  
Gambiae Complex ◽  
Anopheles Gambiae Complex ◽  
Sporozoite Infection

The ability of Anopheles gambiae complex mosquitoes to transmit Plasmodium infection is known to be variable within sibling species of the complex with strains that cannot transmit the parasite. High sporozoite infection rate recorded showed that A. gambiae mosquitoes are potent malaria vectors in southwestern Nigeria. The aim of this study was to identify the infective and refractory strains of A. gambiae mosquitoes and to determine the sporozoite infection rate in this area. The infective strains were A. gambiae (sensu stricto) and A. arabiensis, while the refractory strains were A. gambiae (sensu stricto). However, ovarian polytene chromosome banding patterns could not be used to distinguish between the infective and refractory strains of A. gambiae (sensu stricto). This study showed that the refractory strains of Anopheles gambiae complex are present, but in low frequencies, in southwestern Nigeria, and that the sibling species of Anopheles gambiae (A. gambiae s.s. and A. arabiensis) are potent malaria vectors.

Comparative studies on sibling species of the Anopheles gambiae Giles complex (Dipt., Culicidae). II. Ecology of species A and B in savanna around Kaduna, Nigeria, during transition from wet to dry season

1973 ◽  
Vol 62 (4) ◽  
pp. 613-625 ◽  
Author(s):  
G. B. White ◽  
P. Rosen
Keyword(s):  
Anopheles Gambiae ◽  
Wuchereria Bancrofti ◽  
Black Body ◽  
Intensive Study ◽  
Differential Distribution ◽  
Breeding Sites ◽  
Blood Indices ◽  
Adult Females ◽  
Insect Predators ◽  
Anopheles Gambiae Giles

An intensive study was made of the ecology of species A and B of the Anopheles gambiae Giles complex at Kaduna, Nigeria, in October 1971. In collections comprising 383 larvae and 678 adult females from six villages, species A represented 82% of the larvae and 86, 89 and 91% respectively of the adult females caught by spray catches indoors, by biting catches outdoors and by exit traps fitted to windows. Larvae of species A and B occurred together in 42% of 57 breeding sites and showed no differential distribution among the various categories of site. Minor variations among the proportions of A and B females captured by different methods in the six villages showed no consistent contrasts. The only significant variation of the A/B ratio occurred at a temporary Fulani camp of cattle herdsmen, near Anguwun Maaza village, where an enhanced number of species B females were present indoors. At this Fulani camp a considerable number of both A and B females were feeding on cows outdoors and resting indoors during the day. Human blood indices of indoor-resting females were 88% for species A and 39% for species B at this camp, compared with 100% for both species at villages without cattle. Larval breeding places harboured an expectable range of insect predators. Predators of adult A. gambiae were not investigated although a predacious Emesine bug, Tinna elongata Villiers, was recorded in some huts. Numerous pathogen infections of larvae were observed, namely, Thelohania in 19%, Coelomomyces in 16%, unidentified gregarines in 7% and black-body virus in 3% of gambiae-positive breeding sites. Thelohania, Coelomomyces and gregarine infections were also encountered in adult females. Malaria sporozoite rates were 9·3% in species A and 5·5% in species B females. Some infections of stage III larvae of Wuchereria bancrofti were also seen in species A females.

scholarly journals Temporal Distribution and Abundance of Mosquito Vectors in Dhaka City

2021 ◽  
Vol 46 (1) ◽  
pp. 27-35
Author(s):  
MG Sharower ◽  
MA Latif ◽  
SM Uddin
Keyword(s):  
Anopheles Gambiae ◽  
Sibling Species ◽  
Rainy Season ◽  
Temporal Distribution ◽  
Malaria Vectors ◽  
Dhaka City ◽  
Mosquito Vectors ◽  
Anopheles Gambiae S.S ◽  
Culex Fatigans ◽  
Highly Correlated

Species of Anopheles, Aedes and Culex mosquitoes showed that Anopheles gambiae s.s had the highest number (43.5%) out of the three malaria vectors (viz. Anopheles gambiae, An. arabiensis and An. funestus). For Aedes and Culex species, Aedes aegypti (37.6%) and Culex fatigans (37.1%) had the highest prevalence out of their sibling species. Temperature and rainfall were highly correlated with the abundance of mosquito vectors. It was observed that the rainy season (March to October) recorded the highest number (Total 11 specie) of mosquito vectors collected with the peak (Aedes aegypty, 140) in the months of July (932) and August (976) while the lowest (333) collection was in the dry season (November to February) with lowest (333) in the month of February when there was little or no rains. Asiat. Soc. Bangladesh, Sci. 46(1): 27-35, June 2020

scholarly journals High malaria transmission sustained by Anopheles gambiae s.l. occurring both indoors and outdoors in the city of Yaoundé, Cameroon

2018 ◽  
Vol 3 ◽  
pp. 164 ◽  
Author(s):  
Patricia Doumbe-Belisse ◽  
Carmene Sandra Ngadjeu ◽  
Nadege Sonhafouo-Chiana ◽  
Abdou Talipouo ◽  
Landre Djamouko-Djonkam ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Malaria Transmission ◽  
Public Health Problem ◽  
Transmission Risk ◽  
Malaria Vectors ◽  
Major Public Health Problem ◽  
Infection Status ◽  
Mosquito Abundance ◽  
Biting Rate ◽  
The City

Background: Malaria remains a major public health problem in Cameroon; however, despite reports on the adaptation of anopheline species to urban habitats, there is still not enough information on malaria transmission pattern in urban settings. In the frame of a larval control trial in the city of Yaoundé, we conducted baseline surveys to assess malaria transmission dynamics in this city. Methods: Adult mosquitoes were collected indoors and outdoors using CDC light traps and human landing catches from March 2017 to March 2018 in 30 districts of Yaoundé, Cameroon. Mosquitoes were sorted by genus and identified to the species level using PCR. The TaqMan method and ELISA were used to determine mosquito infection status to Plasmodium. Bioassays were conducted to assess female Anopheles gambiae susceptibility to insecticides. Results: A total of 218,991 mosquitoes were collected. The main malaria vectors were An. gambiae s.l. (n=6154) and An. funestus s.l. (n=229). Of the 1476 An. gambiae s.l. processed by PCR, 92.19% were An. coluzzii and 7.81% An. gambiae. An. funestus s.l. was composed of 93.01% (173/186) An. funestus and 4.84% (13/186) An. leesoni. The average biting rate of anopheline was significantly high outdoor than indoor (P=0.013). Seasonal variation in mosquito abundance and biting rate was recorded. The infection rate by Plasmodium falciparum was 2.13% (104/4893 mosquitoes processed). The annual entomological inoculation rate was found to vary from 0 to 92 infective bites/man/year (ib/m/y). Malaria transmission risk was high outdoor (66.65 ib/m/y) compared to indoor (31.14 ib/m/y). An. gambiae s.l. was found highly resistant to DDT, permethrin and deltamethrin. High prevalence of the West Africa kdr allele 1014F was recorded and this was not found to influence An. gambiae s.l. infection status.   Conclusion: The study suggests high malaria transmission occurring in the city of Yaoundé and call for immediate actions to improve control strategies.

scholarly journals A Simple Key for Identifying the Sibling Species of the Malaria Vector Anopheles gambiae (Giles) Complex by Polytene Chromosome Cytogenetics

2018 ◽  
Vol 10 (1) ◽  
pp. 97-101
Author(s):  
Music Temitope OBEMBE ◽  
Idowu AWOPETU ◽  
Michael AWODIRAN
Keyword(s):  
Anopheles Gambiae ◽  
Polytene Chromosome ◽  
Malaria Vector ◽  
Sibling Species ◽  
Developed Countries ◽  
Sensu Stricto ◽  
Identification Key ◽  
Sub Saharan Africa ◽  
Malaria Vectors ◽  
Gambiae Complex

It has been established that Anopheles gambiae complex sibling species are the major Plasmodium malaria vectors in Africa; however, not all the sibling species transmit the infection. Easier molecular methods, PCR-based assays, have been developed to distinguish the several members of the A. gambiae complex. However, malaria vector research in less developed countries, particularly sub-Saharan Africa, is being hampered by the lack of PCR facilities in laboratories and the cost of carrying out the assay within lack of funding. Hence, the present study was designed to develop a simple identification key, based on an affordable method of polytene chromosome cytotaxonomy, for identifying the major P. falciparum vectors. The Identification Key was successfully used to identify two members of the A. gambiae complex, A. gambiae sensu stricto and A. arabiensis, which are the most potent malaria vectors in Africa; even so, it could not be used to establish the infective and the refractory strains.

scholarly journals Insecticide resistance status of malaria vectors Anopheles gambiae (s.l.) of southwest Burkina Faso and residual efficacy of indoor residual spraying with microencapsulated pirimiphos-methyl insecticide

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Dieudonné Diloma Soma ◽  
Barnabas Zogo ◽  
Domonbabele François de Sales Hien ◽  
Aristide Sawdetuo Hien ◽  
Didier Alexandre Kaboré ◽  
...  
Keyword(s):  
Insecticide Resistance ◽  
Burkina Faso ◽  
Anopheles Gambiae ◽  
Local Population ◽  
Residual Activity ◽  
Indoor Residual Spraying ◽  
Susceptible Strain ◽  
Malaria Vectors ◽  
Pirimiphos Methyl ◽  
Residual Efficacy

Abstract Background The rapid spread of insecticide resistance in malaria vectors and the rebound in malaria cases observed recently in some endemic areas underscore the urgent need to evaluate and deploy new effective control interventions. A randomized control trial (RCT) was conducted with the aim to investigate the benefit of deploying complementary strategies, including indoor residual spraying (IRS) with pirimiphos-methyl in addition to long-lasting insecticidal nets (LLINs) in Diébougou, southwest Burkina Faso. Methods We measured the susceptibility of the Anopheles gambiae (s.l.) population from Diébougou to conventional insecticides. We further monitored the efficacy and residual activity of pirimiphos-methyl on both cement and mud walls using a laboratory susceptible strain (Kisumu) and the local An. gambiae (s.l.) population. Results An. gambiae (s.l.) from Diébougou was resistant to DDT, pyrethroids (deltamethrin, permethrin and alphacypermethrin) and bendiocarb but showed susceptibility to organophosphates (pirimiphos-methyl and chlorpyrimiphos-methyl). A mixed-effect generalized linear model predicted that pirimiphos-methyl applied on cement or mud walls was effective for 210 days against the laboratory susceptible strain and 247 days against the local population. The residual efficacy of pirimiphos-methyl against the local population on walls made of mud was similar to that of cement (OR = 0.792, [0.55–1.12], Tukey’s test p-value = 0.19). Conclusions If data on malaria transmission and malaria cases (as measured trough the RCT) are consistent with data on residual activity of pirimiphos-methyl regardless of the type of wall, one round of IRS with pirimiphos-methyl would have the potential to control malaria in a context of multi-resistant An. gambiae (s.l.) for at least 7 months.

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