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1.
Mem. Inst. Oswaldo Cruz ; 116: e200513, 2021. tab, graf
Article in English | LILACS | ID: biblio-1154879

ABSTRACT

BACKGROUND Different strategies for improvement of malaria control and elimination are based on the blockage of malaria parasite transmission to the mosquito vector. These strategies include the drugs that target the plasmodial sexual stages in humans and the early developmental stages inside mosquitoes. OBJECTIVES Here we tested Malaria Box compounds in order to evaluate their activity against male and female gametocytes in Plasmodium berghei, mosquito infection in P. vivax and ookinete formation in both species. METHODS/FINDINGS The membrane feeding assay and the development of ookinetes by a 24 h ex vivo culture and the ookinete yield per 1000 erythrocytes were used to test transmission-blocking potential of the Malaria Box compounds in P. vivax. For P. berghei we used flow cytometry to evaluate male and female gametocyte time course and fluorescence microscopy to check the ookinete development. The two species used in this study showed similar results concerning the compounds' activity against gametocytes and ookinetes, which were different from those in P. falciparum. In addition, from the eight Malaria Box compounds tested in both species, compounds MMV665830, MMV665878 and MMV665941 were selected as a hit compounds due the high inhibition observed. CONCLUSION Our results showed that P. berghei is suitable as an initial screening system to test compounds against P. vivax.


Subject(s)
Animals , Plasmodium berghei/drug effects , Plasmodium vivax/drug effects , Malaria, Vivax/prevention & control , Mosquito Vectors/parasitology , Malaria, Vivax/drug therapy , Malaria, Vivax/transmission
2.
Mem. Inst. Oswaldo Cruz ; 115: e200070, 2020. tab, graf
Article in English | LILACS, SES-SP | ID: biblio-1135278

ABSTRACT

BACKGROUND Nyssorhynchus deaneorum is a potential malaria vector because it has been shown to be competent to transmit Plasmodium vivax and Plasmodium falciparum, and because it exhibits antropophilic and endophilic behaviors in some regions of the Amazon. This profile makes Ny. deaneorum a useful mosquito for experiments that model Plasmodium-vector interactions in the Amazon. OBJECTIVE Herein we describe how a free-mating colony of Ny. deaneorum has been established using an automated light stimulation system. METHODS Mosquitoes were captured in São Francisco do Guaporé, Rondônia. The F1 generation was reared until adult emergence at which point copulation was induced using an automatic copulation induction system (ACIS). FINDINGS After four generations, natural mating and oviposition began to occur without light stimulation. The number of pupae and adult mosquitoes increased from the F5 to F10 generations. The new Ny. deaneorum colony exhibited susceptibility to P. vivax. MAIN CONCLUSIONS Automated light stimulation is an effective method for establishing an Ny. deaneorum colony under laboratory conditions as it produces enough adults to create a stenogamic colony. The establishment of a stable, P. vivax-susceptible colony of Ny. deaneorum makes it possible to model parasite-vector interactions and to test novel drug therapies that target parasite development in mosquitoes.


Subject(s)
Animals , Female , Oviposition , Copulation/physiology , Mosquito Vectors/parasitology , Insect Vectors/growth & development , Malaria , Anopheles/parasitology , Plasmodium falciparum , Plasmodium vivax , Brazil , Insect Vectors/physiology , Anopheles/physiology
3.
Mem. Inst. Oswaldo Cruz ; 115: e200043, 2020. tab, graf
Article in English | LILACS, SES-SP | ID: biblio-1135250

ABSTRACT

BACKGROUND The number of malaria cases in Roraima nearly tripled from 2016 to 2018. The capital, Boa Vista, considered a low-risk area for malaria transmission, reported an increasing number of autochthonous and imported cases. OBJECTIVES This study describes a spatial analysis on malaria cases in an urban region of Boa Vista, which sought to identify the autochthonous and imported cases and associated them with Anopheles habitats and the potential risk of local transmission. METHODS In a cross-sectional study at the Polyclinic Cosme e Silva, 520 individuals were interviewed and diagnosed with malaria by microscopic examination. Using a global positional system, the locations of malaria cases by type and origin and the breeding sites of anopheline vectors were mapped and the risk of malaria transmission was evaluated by spatial point pattern analysis. FINDINGS Malaria was detected in 57.5% of the individuals and there was a disproportionate number of imported cases (90.6%) linked to Brazilian coming from gold mining sites in Venezuela and Guyana. MAIN CONCLUSIONS The increase in imported malaria cases circulating in the west region of Boa Vista, where there are positive breeding sites for the main vectors, may represent a potential condition for increased autochthonous malaria transmission in this space.


Subject(s)
Humans , Animals , Male , Female , Adult , Plasmodium/isolation & purification , Travel , Miners/statistics & numerical data , Mosquito Vectors/parasitology , Malaria/diagnosis , Malaria/transmission , Anopheles/parasitology , Plasmodium/classification , Urban Population , Venezuela , Brazil/epidemiology , Cross-Sectional Studies , Geographic Information Systems , Spatial Analysis , Gold , Guyana , Malaria/parasitology , Malaria/epidemiology , Anopheles/classification , Middle Aged
4.
Rev. Soc. Bras. Med. Trop ; 52: e20190308, 2019. graf
Article in English | LILACS | ID: biblio-1057242

ABSTRACT

Abstract Malaria, a mosquito-borne infectious disease, is considered a significant global health burden. Climate changes or different weather conditions may impact infectious diseases, specifically those transmitted by insect vectors and contaminated water. Based on the current predictions for climate change associated with the increase in carbon dioxide concentrations in the atmosphere and the increase in atmospheric temperature, the Intergovernmental Panel on Climate Change predicts that in 2050, malaria may threaten some previously unexposed areas worldwide and cause a 50% higher probability of malaria cases. Climate-based distribution models of malaria depict an increase in the geographic distribution of the disease as global environmental temperatures and conditions worsen. Researchers have studied the influence of changes in climate on the prevalence of malaria using different mathematical models that consider different variables and predict the conditions for malaria distribution. In this context, we conducted a mini-review to elucidate the important aspects described in the literature on the influence of climate change in the distribution and transmission of malaria. It is important to develop possible risk management strategies and enhance the surveillance system enhanced even in currently malaria-free areas predicted to experience malaria in the future.


Subject(s)
Animals , Climate Change , Mosquito Vectors/parasitology , Malaria/transmission , Anopheles/parasitology , Population Dynamics , Models, Biological
5.
Mem. Inst. Oswaldo Cruz ; 113(2): 111-118, Feb. 2018. tab, graf
Article in English | LILACS, SES-SP | ID: biblio-894892

ABSTRACT

BACKGROUND In southeastern Brazil, autochthonous cases of malaria can be found near Atlantic Forest fragments. Because the transmission cycle has not been completely clarified, the behaviour of the possible vectors in those regions must be observed. A study concerning the entomological aspects and natural infection of anophelines (Diptera: Culicidae) captured in the municipalities of the mountainous region of Espírito Santo state was performed in 2004 and 2005. Similarly, between 2014 and 2015, 12 monthly collections were performed at the same area of the study mentioned above. METHODS Center for Disease Control (CDC) light traps with CO2 were set in open areas, at the edge and inside of the forest (canopy and ground), whereas Shannon traps were set on the edge. FINDINGS A total of 1,414 anophelines were collected from 13 species. Anopheles (Kerteszia) cruzii Dyar and Knab remained the most frequently captured species in the CDC traps set in the forest canopy, as well as being the vector with the highest prevalence of Plasmodium vivax/simium infection, according to molecular polymerase chain reaction techniques. CONCLUSIONS P. vivax/simium was found only in abdomens of the mosquitoes of the subgenus Nyssorhynchus, weakening the hypothesis that this subgenus also plays a role in malaria transmission in this specific region.


Subject(s)
Mosquito Vectors/parasitology , Malaria/transmission , Anopheles/classification , Anopheles/parasitology , Brazil , Forests , Population Density , Malaria
6.
Rev. Soc. Bras. Med. Trop ; 50(4): 483-488, July-Aug. 2017. tab
Article in English | LILACS | ID: biblio-896987

ABSTRACT

Abstract INTRODUCTION The control of reservoirs for Leishmania infantum -induced zoonotic visceral leishmaniasis requires the identification of dogs posing a population risk. Here, we assessed the performance of several assays to identify Lutzomyia longipalpis infectious dogs. METHODS We evaluated 99 dogs that were positive for visceral leishmaniasis based on parasite identification. Serological analyses were performed using an enzyme-linked immunosorbent assay, immunofluorescence antibody tests in 1:40 and 1:80 dilutions, rapid dual path platform tests, immunochromatographic assay with a recombinant rK39 antigen, fast agglutination screening tests, and direct agglutination tests. We also performed PCR to analyze peripheral blood and xenodiagnosis. RESULTS Forty-six dogs infected at least one L. longipalpis specimen. Although the serological test sensitivities were above 85% for detecting L. longipalpis infectious dogs, none showed a satisfactory performance, as both specificity (0.06 to 13%) and the area under the receiver operating characteristic curve (45 to 53%) were low. The PCR results were also weak, with a sensitivity of 30%, specificity of 72%, and an area under the receiver operating characteristic curve of 51%. The infected L. longipalpis proportion was higher among asymptomatic dogs than symptomatic dogs. Among the symptomatic dogs, those with ulceration-free skin diseases were more infectious, with an odds ratio of 9.3 (confidence interval of 1.10 - 428.5). The larger the number of insects fed, the greater the detected infectiousness. CONCLUSIONS Our study supports the imperative to develop novel technologies for identifying the infectious dogs that transmit L. infantum for the benefit of public health.


Subject(s)
Humans , Animals , Male , Dogs , Psychodidae/parasitology , Serologic Tests/veterinary , Antibodies, Protozoan/blood , Leishmania infantum , Dog Diseases/diagnosis , Mosquito Vectors/parasitology , Leishmaniasis, Visceral/veterinary , Serologic Tests/methods , Sensitivity and Specificity , Dog Diseases/parasitology , Dog Diseases/transmission , Leishmaniasis, Visceral/diagnosis , Leishmaniasis, Visceral/parasitology , Leishmaniasis, Visceral/transmission
7.
Acta pediátr. hondu ; 5(1-2): 336-342, abr.-sep. 2014. tab.
Article in Spanish | LILACS | ID: biblio-884462

ABSTRACT

Antecedentes y objetivos: La fiebre Chikun- gunya (CHIKF) es una enfermedad de infección viral causada por un arbovirus (CHIKV), transmi- tida a los humanos a través de la picadura del mosquito de género Aedes. El objetivo del estudio fué caracterizar clínica y epidemiológi- camente los pacientes que presentaron dicha enfermedad. Pacientes y Métodos: Se realizó un estudio descriptivo transversal en el área de emergencia pediátrica del Hospital Regional del Norte - Instituto Hondureño de Seguridad Social (HRN-IHSS). Los datos se obtuvieron de las fichas epidemiológicas de los casos sospe- chosos de CHIKF que asistieron a la emergencia de pediatría entre los meses de enero y marzo del 2015. Se estudiaron 48 pacientes que cum- plieron con los criterios de inclusión. Resulta- dos: El 52% de los pacientes ingresados prove- nían del casco urbano de San Pedro Sula (SPS). El 63% de los casos asistieron al hospital cuando presentaban de 1 a 2 días de evolución. El síntoma que se presentó con mayor frecuen- cia fue la fiebre (96%), seguido de rash (71%), la artritis y artralgias se presentaron en el 58% de los casos. En el 75% de los casos había fami- liares con síntomas similares. Conclusiones: Los lactantes menores y los escolares del sexo masculino fueron los más afectados, y no hubo antecedente de haber realizado viajes previos...(AU)


Subject(s)
Humans , Child , Aedes/virology , Arbovirus Infections/complications , Chikungunya Fever/diagnosis , Mosquito Vectors/parasitology
8.
Mem. Inst. Oswaldo Cruz ; 84(supl.4): 501-503, 1989. tab
Article in Portuguese | LILACS | ID: lil-623917

ABSTRACT

In a small forest of 4ha placed inside the Ecologic Campus of Federal University of Minas Gerais, Belo Horizonte, were made captures of mosquitoes each fifteen days (during the day and the night) in a complete year: March 1988 to February, 1989. The daylight captures were made on human bait and the night captures were made with New Jersey trap. Sixty one captures were made, yielding 497 specimens of 15 species.


Subject(s)
Culicidae/anatomy & histology , Culicidae/classification , Mosquito Vectors/parasitology
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