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1.
Zoo Biol ; 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38685797

RESUMO

The white-bellied pangolin Phataginus tricuspis (Rafinesque 1821) is a semiarboreal species occurring in tropical sub-Saharan Africa. It is the world's most trafficked African pangolin species based on volumes recorded in seizures. Reintroduction of confiscated live pangolins and ex-situ rearing are being explored worldwide as a conservation action. However, the husbandry of seized animals is challenging as the diet of the white-bellied pangolin is poorly known and little studied. We analyzed the stomach contents of dead white-bellied pangolins from two forest-savanna protected areas. Stomach content samples from 13 white-bellied pangolin specimens contained ~165,000 Arthropoda, mostly Hymenoptera (60.34%) and Blattodea (39.66%). Overall, we identified 39 termite and 105 ant species consumed as prey by pangolins. Individual pangolins examined had fed on a maximum of 31 ant species and 13 termite species. The termite and ant species richness varied significantly across the pangolins' last consumed meal. We recorded 24 ant genera dominated by Crematogaster (relative importance [RI] = 17.28). Out of 18 termite genera recorded, the genus Pseudacanthotermes (RI = 17.21) was the most important prey. Ten ant species were preferentially eaten by white-bellied pangolin, with Crematogaster acis being the most common prey species. Four species of termite were most frequently eaten with Pseudacanthotermes militaris being the most abundant. The mean abundance of ants and termites varied among pangolin individuals. The season did not influence the mean abundance of termites eaten by pangolin individuals. However, ant abundance in stomach contents was significantly higher in the dry season. An improved understanding of pangolin feeding behavior and prey selection may help inform conservation husbandry efforts. For example, nutritional analysis of the food eaten by wild pangolins can guide the development of nutritional diets for captive pangolins.

2.
Pestic Biochem Physiol ; 195: 105569, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37666599

RESUMO

BACKGROUND: Larviciding using non-insecticide compounds is considered appropriate for controlling outdoor biting mosquitoes and for managing insecticide resistance. However, there is still not enough information on the influence of larviciding in managing pyrethroid resistance. In the present study, we checked whether the introduction of larviciding using the biolarvicide VectoMax G in the city of Yaoundé is contributing in restoring the susceptibility of An. coluzzii populations to pyrethroids. METHODOLOGY: The susceptibility status of field An. coluzzii population was evaluated at different time points before and during larviciding treatments. In addition, An. coluzzii larvae collected in the city of Yaoundé, were split into four groups and exposed to different selection regimes for many generations as follow; (i): deltamethrin 0.05%_only, (ii): Vectomax_only, (iii): Vectomax+deltamethrin 0.05%, (iv): VectoMax+deltamethrin 0.05% + susceptible. Life traits parameters were measured in the progeny and compared between colonies. The control was the susceptible laboratory strain "Ngousso". Kdr allele frequency and the profile of expression of different detoxification genes and oxidative stress genes was checked using qPCR analysis. Gene's expression was compared between the first and the last generation of each colony and in field populations collected before and during larviciding. RESULTS: An increase in mosquito susceptibility to deltamethrin and permethrin was recorded for the field populations after larviciding implementation. Resistance intensity to deltamethrin was found to decrease from high to low in field populations. Only the colony vectomax+deltamethrin+susceptible presented a high susceptibility to deltamethrin after 21 generations. The kdr gene frequency was found to be unchanged in the field population and laboratory colonies. A significant decrease in the overexpression profile of Gste2 was detected in field population after larviciding implementation. Other genes showing a similar pattern though not significant were Cyp6z1, Cyp6p1 and Cyp6g16. Concerning fitness only the colony vectomax+deltamethrin+susceptible was found to display a fitness profile similar to the susceptible colony with high fecundity, high hatching rate, short development time and long adult survival rate. CONCLUSION: The profile of the field population supported reversal of phenotypic resistance to pyrethroids however no reduction in the frequency of the kdr allele was recorded. Some detoxification genes were detected less overexpressed. The study suggest that reversal may take longer to achieve in a population expressing a very high resistance profile and under continuous insecticide selection pressure.


Assuntos
Anopheles , Inseticidas , Animais , Anopheles/genética , Camarões , Permetrina , Inseticidas/farmacologia
3.
Artigo em Inglês | MEDLINE | ID: mdl-37693015

RESUMO

Although Culex species are considered to be equally affected by control measures targeting malaria vectors, there is still not enough evidence of the impact of interventions such as larviciding on the distribution of these mosquito species. The present study assessed the impact of a larviciding trial targeting malaria vectors on Culex mosquito species in the city of Yaoundé, Cameroon. A cluster randomized trial comparing 13 treated clusters and 13 untreated clusters was implemented. Data were collected at baseline and during the larviciding intervention, from March 2017 to November 2020. The microbial larvicide VectoMax G was applied once every 2 weeks in the intervention areas. Adult mosquitoes were collected using CDC light traps in both intervention and non-intervention areas and compared between arms. Globally, larviciding intervention was associated with 69% reduction in aquatic habitats with Culex larvae and 36.65% reduction of adult Culex densities in houses. Adult Culex densities were reduced both indoors (35.26%) and outdoors (42.37%). No change in the composition of Culex species was recorded. The study suggests a high impact of larviciding on Culex mosquito species distribution. The impact of the intervention can be improved if typical Culex breeding habitats including pit latrines are targeted.

4.
Trop Med Infect Dis ; 8(5)2023 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-37235292

RESUMO

Evaluating the susceptibility of malaria vectors to the new WHO-recommended products is a key step before large-scale deployment. We mapped the susceptibility profile of Anopheles funestus to neonicotinoids across Africa and established the diagnostic doses of acetamiprid and imidacloprid with acetone + MERO as solvent. Indoor resting An. funestus were collected in 2021 in Cameroon, Malawi, Ghana and Uganda. Susceptibility to clothianidin, imidacloprid and acetamiprid was evaluated using CDC bottle assays and offsprings of the field-caught adults. The L119F-GSTe2 marker was genotyped to assess the potential cross-resistance between clothianidin and this DDT/pyrethroid-resistant marker. Mosquitoes were susceptible to the three neonicotinoids diluted in acetone + MERO, whereas low mortality was noticed with ethanol or acetone alone. The doses of 6 µg/mL and 4 µg/mL were established as diagnostic concentrations of imidacloprid and acetamiprid, respectively, with acetone + MERO. Pre-exposure to synergists significantly restored the susceptibility to clothianidin. A positive correlation was observed between L119F-GSTe2 mutation and clothianidin resistance with the homozygote resistant mosquitoes being more able to survive than heterozygote or susceptible. This study revealed that An. funestus populations across Africa are susceptible to neonicotinoids, and as such, this insecticide class could be effectively implemented to control this species using IRS. However, potential cross-resistance conferred by GSTe2 calls for regular resistance monitoring in the field.

5.
Ecol Evol ; 13(5)2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37181204

RESUMO

Pangolin species are notoriously difficult to detect and monitor in the wild and, as a result, commonly used survey techniques fall short in gathering sufficient data to draw confident conclusions on pangolin populations, conservation status, and natural history. The white-bellied pangolin is a semiarboreal species that may be poorly detected in general mammal surveys even with modern techniques such as camera-trapping. As a result, population status information is often derived from hunting, market, and trafficking data. There is therefore a crucial need to improve camera-trap survey methods to reliably detect this species in its natural environment. Here, we test the influence of camera-trap placement strategy on the detectability of the white-bellied pangolin by comparing estimates from targeted ground-viewing camera-trapping and a novel log-viewing placement strategy adapted from local hunters' knowledge. Our results suggest that (1) deploying camera-traps to detect animals walking along logs is an effective strategy for recording several forest species, including the white-bellied pangolin, and (2) that camera-traps targeting logs are more efficient at detecting white-bellied pangolins than camera-traps viewing the ground (>100% increase in detection probability). We also found moderate evidence that there is a relationship between the white-bellied pangolin occurrence at our locality and elevation and weak evidence of an association with distance to the nearest river. Our results suggest an effective new monitoring approach allowing consistent detection of the white-bellied pangolin with moderate survey effort. This highlights the importance of harnessing local knowledge to guide the design of monitoring protocols for cryptic species.

6.
J Insect Sci ; 23(2)2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36934305

RESUMO

The sensitivity of grasshoppers to disturbance makes them useful bioindicators for land management. The current study compared the grasshopper communities of three fallow-lands at different levels of human pressure: heavily used land (Ongot), moderately used land (Zamakoe), and least-used land (Ngutadjap). Grasshoppers were sampled by nets, pitfall traps, and box quadrats. Their species composition was analyzed using species-richness, abundance, abundance distribution-model, occurrence, and diversity indexes. Species number was not very different between localities. However, the opening up of forests by human activities offers suitable environment for the development or proliferation of the pest grasshopper populations such as Zonocerus variegatus (Linnaeus, 1758), Eyprepocnemis plorans (Charpentier, 1825), and Catantops sylvestrisJago, 1984, which are adapted to the very common Asteraceae found in fallow lands. Native forest species [such as Mazaea granulosa Stål, 1876, Holopercna gerstaeckeri (Bolívar, 1890), Digentia fasciataRamme, 1929] were, generally absent or rare and were collected in only forest/fallow-land ecotones. Low abundance and low occurrence of ecotone species fitted the log-normal abundance distribution model. The grasshopper communities of the less degraded localities were quite similar, but different from the Ongot community. Forest management by reforestation, reduction of slash-and-burn agriculture, and wood cutting, would restore the original grasshopper assemblages and general environmental health.


Assuntos
Gafanhotos , Humanos , Animais , Conservação dos Recursos Naturais , Camarões , Florestas , Agricultura , Biodiversidade
7.
Zootaxa ; 5336(3): 373-388, 2023 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-38221089

RESUMO

The taxonomy of the genus Brachytrupes Serville, 1838, known as Giant Burrowing Crickets is revised. Brachytrupes includes thirteen species, with B. megacephalus Lefebvre, 1827 designated as type species to promote nomenclature stability. Brachytrupes membranaceus Drury 1773, is regarded as a nomen dubium. Furthermore, the present study provides a description of a new species Brachytrupes bapaensis Simeu-Noutchom, Kekeunou & Heller sp. nov. from West Cameroon, together with a species identification key and geographic distribution. Brachytrupes bapaensis sp. nov. can be distinguished from all other species of the genus by its black-brown body, pronotum smooth and black with a yellow spot on the lateral margin, posterior pronotum as wide as the anterior. Moreover, calling song with the syllable period around 8 ms and the syllable repetition rate near 115 Hz have been recorded. This review has wide implications for the knowledge of edible insects as well as their distribution.


Assuntos
Gryllidae , Ortópteros , Animais , Distribuição Animal , Estruturas Animais , Tamanho Corporal
8.
Zootaxa ; 5369(4): 591-596, 2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-38220696

RESUMO

During a Gryllidae survey in the Southern Cameroonian Plateau, one new species of the genus Gymnogryllus (Orthoptera, Gryllidae, Gryllinae) was discovered and described, namely Gymnogryllus bilongi Um Nyobe & Kekeunou sp. nov. This finding extends the number of species known of this genus in Cameroon at two and proposes a key for African species.


Assuntos
Gryllidae , Ortópteros , Animais , Camarões , Distribuição Animal , Tamanho Corporal , Estruturas Animais , Tamanho do Órgão
9.
PLoS One ; 17(11): e0276500, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36327271

RESUMO

BACKGROUND: Urban malaria is becoming a major public health concern in major cities in Cameroon. To improve malaria vector control, a pilot larviciding trial was conducted to assess its impact on mosquito density and malaria transmission intensity in Yaoundé. The present study investigated perceptions and practices of communities on malaria control during the larviciding trial implemented in Yaoundé. METHODS: Quantitative and qualitative data were collected in non-intervention and intervention areas. Quantitative data were collected during three cross-sectional surveys using a structured pre-tested questionnaire while qualitative data were obtained through interviews. A total of 26 in-depth interviews and eight focus group discussions with community members were performed. A binary logistic regression model was used to assess the perception of the community on larviciding impact on some malaria or bed nets use indicators. RESULTS: People living in intervention areas were 2.64 times more likely to know the mode of malaria transmission (95% CI: 1.82-3.84; p<0.001) and 1.3 time more likely to know mosquito breeding habitats (95% CI: 1.06-1.56; p = 0.009) compared to those living in non-intervention areas. In intervention areas, interviewee opinions on larviciding were generally good i.e. most interviewees reported having noticed a reduction in mosquito nuisance and malaria cases following larviciding implementation; whereas in non-intervention areas no report of reduction of mosquito nuisance was recorded. LLINs were regularly used by the population despite the implementation of larviciding treatments. There was high interest in larviciding program and demand for continuation, even if this needs the community involvement. CONCLUSION: The larviciding program in the city of Yaoundé did not negatively affected community members' behaviour and practices concerning the use of treated nets. The study indicated the acceptance of larviciding program by the population. This positive environment could favour the implementation of future antilarval control activities in the city of Yaoundé.


Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Malária , Animais , Humanos , Camarões/epidemiologia , Cidades/epidemiologia , Estudos Transversais , Malária/epidemiologia , Malária/prevenção & controle , Controle de Mosquitos , Mosquitos Vetores , Grupos Focais , Inquéritos e Questionários , Pesquisa Qualitativa
10.
Sci Rep ; 11(1): 7322, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33795804

RESUMO

Culex mosquitoes particularly Culex quinquefasciatus are important arboviral and filariasis vectors, however despite this important epidemiological role, there is still a paucity of data on their bionomics. The present study was undertaken to assess the insecticide resistance status of Cx. quinquefasciatus populations from four districts of Yaoundé (Cameroon). All Culex quinquefasciatus populations except one displayed high resistance to bendiocarb and malathion with mortalities ranging from 0 to 89% while high resistance intensity against both permethrin and deltamethrin was recorded. Molecular analyses revealed high frequencies of the ACE-1 G119S mutation (ranging from 0 to 33%) and kdr L1014F allele (ranging from 55 to 74%) in all Cx. quinquefasciatus populations. Significant overexpression was detected for cytochrome P450s genes CYP6AA7 and CYP6Z10, as well as for Esterase A and Esterase B genes. The total cuticular hydrocarbon content, a proxy of cuticular resistance, was significantly increased (compared to the S-lab strain) in one population. The study confirms strong insecticide resistance mediated by different mechanisms in Cx. quinquefasciatus populations from the city of Yaoundé. The expansion of insecticide resistance in Culex populations could affect the effectiveness of current vector control measures and stress the need for the implementation of integrated vector control strategies in urban settings.


Assuntos
Culex/efeitos dos fármacos , Resistência a Inseticidas , Inseticidas/farmacologia , Alelos , Animais , Camarões , Entomologia/métodos , Feminino , Perfilação da Expressão Gênica , Geografia , Hidrocarbonetos/química , Proteínas de Insetos/genética , Controle de Mosquitos , Mosquitos Vetores/genética , Mutação , Nitrilas/farmacologia , Permetrina/farmacologia , Dinâmica Populacional , Piretrinas/farmacologia
11.
J Therm Biol ; 97: 102877, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33863442

RESUMO

The oriental fruit fly Bactrocera dorsalis (Diptera: Tephritidae) is a major pest of fruit and vegetable production systems on several continents. The pest has invaded many countries, causing considerable impact on fruit production systems and commercialization. In this study we determined the relationship between temperature and development, survival and reproductive parameters of B. dorsalis on an artificial diet under laboratory conditions under 7 constant temperatures (10, 15, 20, 25, 30, 33 and 35 °C) with 70 ± 10% relative humidity and a photoperiod of L12:D12. We validated the laboratory results with a full life table analysis under semi-natural conditions in a screenhouse. We used the Insect Life Cycle Modeling (ILCYM) software for all mathematical models and simulations applied to all life history parameters. Bactrocera dorsalis completed its development at temperatures ranging between 15 and 33 °C with the mean developmental time of egg, larva, and pupa ranging between 1.46 and 4.31 days, 7.14-25.67 days, and 7.18-31.50 respectively. The models predicted temperatures ranging between 20 and 30 °C as favorable for development and survival, and 20 to 25 °C for optimal fecundity of B. dorsalis. Life table parameters showed the highest gross reproductive rate (GRR), net reproductive rate (Ro), intrinsic rate of increase (rm), and finite rate of increase (λ) between 25 and 31 ᵒC while generation time (T) and doubling time (Dt) were low at this interval. The effects of future climate change on B. dorsalis life history parameters were further investigated and the outcome from this study will help in the management of B. dorsalis in different agroecologies in the context of ongoing climate change.


Assuntos
Modelos Biológicos , Temperatura , Tephritidae , Animais , Feminino , Masculino , Reprodução , Estações do Ano , Tephritidae/crescimento & desenvolvimento , Tephritidae/fisiologia
12.
Zootaxa ; 4915(1): zootaxa.4915.1.6, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33756586

RESUMO

The specimens studied were collected with sweep net and pitfall in the forests, agro-forests, herbaceous fallows, and crop fields of 14 localities in the southern part of Cameroon, from August 2015 to February 2018. The results show that Heteracris hannai sp. nov. and Heteracris lecoqi sp. nov. differ from previously known species of the same genus by the pattern of coloration and the details or shape of the phallic complex. H. lecoqi sp. nov. is characterized by light brownish body; male cercus with flattened, downcurved and obtuse apex; lophus strongly curved; interlophal space with V shape; apodeme of cingulum bow, convergent, with V-shape; valve of cingulum in lateral view longer than apical valve of penis; ramus in ventral view joined. H. hannai sp. nov. is distinct to other species by brown to grey body; male cercus with apex rounded, curved inside; lophus curved; interlophal space with U-shape; apodeme of cingulum thick, slightly parallel, with U shape; valve of cingulum in lateral view hardly longer than apical valve of penis; ramus in ventral view opened. The characteristics of H. guineensis are closer to H. hannai sp. nov. than to H. lecoqi sp. nov. H. lecoqi sp. nov. was collected only in the fallows while H. hannai sp. nov. was collected in the forests, agro-forests, fallows, and crop fields. Compared to H. guineensis, both new species are scarce in the natural vegetation and their distribution area is limited to two and four localities respectively for H. lecoqi sp. nov. and H. hannai sp. nov. All these three grasshopper's species were recorded as accidental species in all types of vegetation.


Assuntos
Gafanhotos , Ortópteros , Distribuição Animal , Animais , Camarões , Masculino
13.
Zootaxa ; 4908(4): zootaxa.4908.4.2, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33756599

RESUMO

The genus Cryncus Gorochov, 1983 composed of African crickets is reported for the first time in Cameroon by the description of two new species collected at Zamakoe, Ongot and Engout'Adjap in the southern Cameroonian plateau during an inventory study of crickets carried out from March 2014 to September 2015. These new species are: Cryncus camerounensis Um Nyobe, Kekeunou Bilong Bilong sp. nov. and Cryncus desutterae Um Nyobe, Kekeunou Ma sp. nov. These descriptions bring the total number of species of this genus to 25. Cryncus camerounensis is distinguished by an irregularly shaped mirror, without a dividing vein, with a short apical field, while Cryncus desutterae is characterized by a divided oval mirror and a long apical field. Cryncus camerounensis was more abundant in the forest environment while Cryncus desutterae would exclusively colonize fallow land. This article is divided into two parts. The first part presents a description of the two new species, followed by a revised diagnosis of the genus Cryncus using both male and female characters and an identification key. The second part presents some bioecological data of these new species and a map of the geographical distribution of all known species of this genus.


Assuntos
Gryllidae , Ortópteros , Distribuição Animal , Estruturas Animais , Animais , Tamanho Corporal , Camarões , Feminino , Masculino , Tamanho do Órgão
14.
Wellcome Open Res ; 5: 171, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33029560

RESUMO

Background: Pyrethroid resistance is rapidly expanding in An. gambiae s.l. populations across Sub-Saharan Africa. Yet there is still not enough information on the fitness cost of insecticide resistance . In the present study, the fitness cost of insecticide resistance on Anopheles coluzzii population from the city of Yaoundé was investigated.   Methods: A resistant An. coluzzii colony was established from field collected mosquitoes resistant to both DDT and pyrethroid and selected for 12 generations with deltamethrin 0.05%. The Ngousso laboratory susceptible strain was used as control. A total of 100 females of each strain were blood fed and allowed for individual eggs laying, and then different life traits parameters such as fecundity, fertility, larval development time, emergence rate and longevity were measured. The TaqMan assay was used to screen for the presence of the L1014F and L1014S kdr mutations. Results:  Field collected mosquitoes from the F0 generation had a mortality rate of 2.05% for DDT, 34.16% for permethrin and 50.23% for deltamethrin. The mortality rate of the F12 generation was 30.48% for deltamethrin, 1.25% for permethrin  and 0% for DDT. The number of eggs laid per female was lower in the resistant colony compared to the susceptible (p <0.0001). Insecticide resistant larvae were found with a significantly long larval development time (10.61±0.33 days) compare to susceptible (7.57±0.35 days). The number of emerging females was significantly high in the susceptible group compared to the resistant . The adults lifespan was also significantly high for susceptible (21.73±1.19 days) compared to resistant (14.63±0.68 days). Only the L1014F- kdr allele was detected in resistant population.. Conclusion: The study suggests that pyrethroid resistance is likely associated with a high fitness cost on An.coluzzii populations. The addition of new tools targeting specifically larval stages could improve malaria vectors control and insecticide resistance management.

15.
Zootaxa ; 4763(1): zootaxa.4763.1.5, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33056879

RESUMO

Gryllotalpa weisei Simeu-Noutchom Kekeunou sp. nov. was collected only in Tombel in the South-West region of Cameroon, during a survey conducted from March 2016 to March 2018 in the West, South-West and Centre regions of Cameroon. This species is close to Gryllotalpa microptera, collected for the first time in Cameroon during these investigations, only in the West region. G. weisei is different from G. microptera due to the hind wings that are vestigial; average fore wings length of 5.85±0.56 mm in male and 5.34±0.45 mm in female, not reaching the fifth abdominal segment; anal end of fore wings slightly concave; a stridulatory file with 54±8.02 teeth (47-71) in average, fairly spaced, with an average of 30±5.06 teeth per millimeter; hind tibia bearing 11 spines; internal process of ectophallus quite short. G. weisei abounds in mixed crop fields, followed by cocoa agro-forests; it is scarce in grassy fallows and in forest undergrowth. G. microptera was present in all types of vegetations in Bafoussam, Babeté and Bangoulap in the West region where it has been abundant in mixed crop fields, grass-fallow and coffee agro-forest but rare in forest undergrowth.


Assuntos
Ortópteros , Animais , Camarões , Feminino , Florestas , Masculino , Inquéritos e Questionários
16.
PLoS One ; 15(9): e0230984, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32946446

RESUMO

Insecticide resistance genes are often associated with pleiotropic effects on various mosquito life-history traits. However, very little information is available on the impact of insecticide resistance on blood feeding process in mosquitoes. Here, using two recently detected DNA-based metabolic markers in the major malaria vector, An. funestus, we investigated how metabolic resistance genes could affect the blood meal intake. After allowing both the field F1 and lab F8 Anopheles funestus strains to feed on the human arm for 30 minutes, we assessed the association between key parameters of blood meal process including, probing time, feeding duration, blood feeding success, blood meal size, and markers of glutathione S-transferase (L119F-GSTe2) and cytochrome P450 (CYP6P9a_R)-mediated metabolic resistance. None of the parameters of blood meal process was associated with L119F-GSTe2 genotypes. By contrast, for CYP6P9a_R, homozygous resistant mosquitoes were significantly more able to blood-feed than homozygous susceptible (OR = 3.3; CI 95%: 1.4-7.7; P = 0.01) mosquitoes. Moreover, the volume of blood meal ingested by CYP6P9a-SS mosquitoes was lower than that of CYP6P9a-RS (P<0.004) and of CYP6P9a-RR (P<0.006). This suggests that CYP6P9a gene is inked with the feeding success and blood meal size of An. funestus. However, no correlation was found in the expression of CYP6P9a and that of genes encoding for salivary proteins involved in blood meal process. This study suggests that P450-based metabolic resistance may influence the blood feeding process of Anopheles funestus mosquito and consequently its ability to transmit malaria parasites.


Assuntos
Anopheles/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Glutationa Transferase/metabolismo , Proteínas de Insetos/metabolismo , Mosquitos Vetores/metabolismo , Animais , Anopheles/efeitos dos fármacos , Anopheles/genética , Anopheles/parasitologia , Sangue/metabolismo , Camarões , Sistema Enzimático do Citocromo P-450/genética , Comportamento Alimentar , Feminino , Glutationa Transferase/genética , Humanos , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Malária/parasitologia , Malária/prevenção & controle , Malária/transmissão , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/genética , Mosquitos Vetores/parasitologia , Plasmodium/patogenicidade , Piretrinas/farmacologia , Proteínas e Peptídeos Salivares/metabolismo
17.
Malar J ; 19(1): 53, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32000786

RESUMO

BACKGROUND: Improving house structure is known to limit contact between humans and mosquitoes and reduce malaria transmission risk. In the present study, the influence of house characteristics on mosquito distribution and malaria transmission risk was assessed in the city of Yaoundé. METHODS: The study was conducted from March 2017 to June 2018 in 32 districts of the city of Yaoundé. Mosquito collections were performed indoor in 10 to 15 houses per district using CDC light traps. A total of 467 houses, selected randomly were used. A pretested questionnaire was submitted to participants of the study to collect information on the household: the number of people per house, education level, type of walls, presence of ceilings and eaves, number of windows, usage of long-lasting insecticidal nets (LLINs), number of bedroom and number of window. Mosquitoes collected were identified morphologically. Anophelines were tested by ELISA to detect infection by Plasmodium parasites. General Estimating Equations adjusting for repeated measures in the same house fitting negative binomial analysis were used to assess the influence of house characteristics on mosquito distribution. RESULTS: A total of 168,039 mosquitoes were collected; Culex spp emerged as the predominant species (96.48%), followed by Anopheles gambiae sensu lato (s.l.) (2.49%). Out of the 1033 An. gambiae s.l. identified by PCR, 90.03% were Anopheles coluzzii and the remaining were An. gambiae sensu stricto (s.s.) (9.97%). The high number of people per household, the presence of screens on window and the possession of LLINs were all associated with fewer mosquitoes collected indoors, whilst opened eaves, the high number of windows, the presence of holes in walls and living close to breeding sites were associated with high densities of mosquitoes indoor. Out of 3557 Anophelines tested using ELISA CSP, 80 were found infected by Plasmodium falciparum parasites. The proportion of mosquitoes infected did not vary significantly according to house characteristics. CONCLUSION: The study indicated that several house characteristics such as, the presence of holes on walls, opened eaves, unscreened window and living close to breeding sites, favored mosquito presence in houses. Promoting frequent use of LLINs and house improvement measures, such as the use of screen on windows, closing eaves, cleaning the nearby environment, should be integrated in strategies to improve malaria control in the city of Yaoundé.


Assuntos
Anopheles/fisiologia , Culex/fisiologia , Habitação/normas , Malária/transmissão , Mosquitos Vetores/fisiologia , Animais , Anopheles/parasitologia , Camarões , Cidades , Culex/parasitologia , Emigração e Imigração , Características da Família , Habitação/classificação , Humanos , Malária/prevenção & controle , Mosquitos Vetores/parasitologia , Inquéritos e Questionários , População Urbana
18.
BMC Public Health ; 19(1): 1040, 2019 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-31376829

RESUMO

BACKGROUND: In Cameroon, since the first epidemiological week held in 2015, snakebites have been registered among Potential Epidemic Diseases (PED). In the Centre Region, the most densely populated of the country, weekly reports of snakebites are generated at health districts level for monthly data updates. METHODS: To contribute to the better management of snakebite cases, an observational study was conducted to assess the snakebite reporting rate in the Centre Region of Cameroon. The results of this retro-prospective survey were confronted to those of the weekly epidemiological surveillance system, recorded in the PED regional data base. RESULTS: The incidence of bites was relatively high (36.6 bites per 100,000 inhabitants), as well as the general attack rate (about 49 envenomations per 100 victims). The lethality recorded was 2.5% and the mortality was about 1 death per 100,000 inhabitants a year. The sex ratio was largely female biased (61.6%). The bites occurred mostly during the rainy season (73.0%). Bitten victims were mainly farmers (47.4%), and agriculture was the main risk factor. The comparative analysis of the data suggested a high non-reporting rate of snakebite cases (67.8%). CONCLUSION: Snakebite is an endemic condition in the Centre Region of Cameroon. Because of the high rate of non-reporting of cases, the collection of information from the registers of the health facilities only appears not enough to assess the real importance of envenomation in this Region.


Assuntos
Prontuários Médicos/estatística & dados numéricos , Mordeduras de Serpentes/epidemiologia , Adulto , Camarões/epidemiologia , Feminino , Humanos , Incidência , Masculino , Estudos Prospectivos , Estudos Retrospectivos , Fatores de Risco , Adulto Jovem
20.
Malar J ; 18(1): 167, 2019 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-31072344

RESUMO

BACKGROUND: Malaria prevention in Cameroon mainly relies on the use of ITNs. Although several free distribution campaigns of treated nets have been conducted across the country, bed net usage remains very low. A household survey was conducted to assess knowledge of the population and practices affecting treated net usage in the city of Yaoundé. METHODS: A community-based descriptive cross-sectional survey was conducted in January 2017 in 32 districts of the city of Yaoundé. Parents (household head, spouse or an elder representative) who consented to the study, were interviewed using a structured pre-tested questionnaire. Interviews were conducted in French or English. A questionnaire consisting of 22 questions was administered to know (i) people's knowledge and attitude on preventive measures; and, (ii) attitudes concerning the treatment of malaria and estimated amount spent for malaria prevention and treatment. RESULTS: A total of 1643 household heads were interviewed. Over 94% of people interviewed associated malaria transmission to mosquito bites. The main methods used against mosquito bites were: treated bed nets (94%; n = 1526) and insecticide spray or coils (32.2%; n = 523). The majority of people interviewed reported using bed nets mainly to prevent from mosquito bites (84.4%, n = 1257), rather than for malaria prevention (47.3%). Knowledge and attitude analysis revealed that people with university or secondary level of education have better knowledge of malaria, prevention and treatment measures compared to those with the primary level (OR = 7.03; P < 0.001). Also, wealthy households were more aware of good practices concerning malaria prevention and treatment compared to poor ones. In the majority of districts of Yaoundé, over 50% of people interviewed per district, had good knowledge of malaria and prevention measures but less than 50% applied good practices concerning malaria treatment and prevention. The amount spent annually by a household for vector control was CFAF 11,589 ± 1133 (US$21.87 ± 2.14) and CFAF 66,403 ± 4012 (US$125.29 ± 7.57) for malaria treatment. CONCLUSION: The study indicated that, despite good knowledge of malaria and prevention measures, few people apply good practices. More sensitization needs to be done to improve adherence to good practices concerning malaria prevention and treatment.


Assuntos
Mordeduras e Picadas/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Malária/prevenção & controle , Controle de Mosquitos/métodos , População Urbana , Adolescente , Adulto , Camarões/epidemiologia , Cidades/epidemiologia , Estudos Transversais , Características da Família , Feminino , Humanos , Mosquiteiros Tratados com Inseticida/estatística & dados numéricos , Malária/epidemiologia , Masculino , Pessoa de Meia-Idade , Controle de Mosquitos/economia , Inquéritos e Questionários , Adulto Jovem
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