Development Of Plasmodium Vivax Research Articles

Influence of Household Roof Types on the Development of Plasmodium vivax in Anopheles stephensi Mosquitoes.

Urbanization and microclimate variation in cities can influence mosquito behavior and parasite development, thus affecting malaria transmission. This study investigates how the impact of microclimate variations due to household roof types can aid in the survival of Anopheles stephensi and the development of Plasmodium vivax in an urban slum setting. Understanding these vital environmental interactions is essential for devising effective control strategies to achieve malaria elimination. Anopheles stephensi (F1) mosquitoes were membrane-fed with blood collected from P. vivax-infected patients before (day 0) and during (day 1) antimalarial treatment. The parasite development and mosquito survival were monitored in simulated microclimatic conditions of a variety of household roof types (thatched, asbestos, tiled) against standard laboratory conditions. Mosquito dissections were undertaken to detect oocysts and sporozoites in An. stephensi mosquitoes (oocyst: day 3-5, sporozoites: day 7-11). The maximum number of oocysts were detected in infected mosquitoes in thatched-roof conditions, whereas the largest oocyst was in the asbestos roof type. Circumsporozoite-ELISA results indicated the presence of sporozoites in infected mosquitoes for up to 29 days under standard conditions, 18 days in thatched-roof and asbestos roof conditions, and 14 days in tiled conditions. The univariate binary logistic regression model indicated a significant influence of microclimatic conditions of thatched roofs on parasite development. The Kaplan-Meier survival analysis revealed that the median survival of P. vivax-infected An. stephensi in thatched-roof conditions was 14 days, followed by asbestos (11 days) and tiled (10 days) roof conditions. In conclusion, thatched-roof houses were favorable for the development and survival of P. vivax-infected An. stephensi.

Seasonal dynamics of Anopheles species at three locations in the Republic of Korea.

Weekly changes in adult Anopheles species were monitored at Camp Humphreys (CH), Ganghwa Island (GH), and Warrior Base (WB), from May-October, 2009-2010 to explore the relationship between Plasmodium vivax development and vector dynamics in the Republic of Korea (ROK). Adult females were trapped and dissected to determine parity for estimating longevity, mortality, and birthrate. A degree-day (DD) method was used to estimate the extrinsic incubation period (EIP) of P. vivax and duration of the gonotrophic cycle and other life stages. Anopheles sinensis was the predominant species, with satellite data showing peak abundance occurring after the period of maximum greenness. Abundance peaks were location dependent, comprised nulliparous and parous females, and timing could not be fully explained by DD estimation. Parity showed synchronicity between locations and years and was highest for September and lowest during maximum greenness. Mosquito longevity was predicted to exceed the EIP (when malaria transmission is possible) during weeks 29, 31, 34, and near the end of the season. Area-wide changes in parity suggest a common cause; information on local larval habitat and agricultural practices may explain location-specific effects. DD estimates of EIP and parity could be used to predict when conditions are suitable for P. vivax transmission.

In silico screening of novel inhibitors of M17 Leucine Amino Peptidase (LAP) of Plasmodium vivax as therapeutic candidate.

M17 LAP (Leucine Amino Peptidase) plays an important role in the hydrolysis of amino acids essential for growth and development of Plasmodium vivax (Pv), the pathogen causing malaria. In this paper a homology model of PvLAP was generated using MODELLER v9.15. From different in-silico methods such as structure based, ligand based and de novo drug designing a total of 90 compounds were selected for docking studies. A final list of 10 compounds was prepared. The study reported the identification of 2-[(3-azaniumyl-2-hydroxy-4-phenylbutanoyl) amino]-4-methylpentanoate as the best inhibitor in terms of docking score and pharmacophoric features. The reliability of the binding mode of the inhibitor is confirmed by molecular dynamics (MD) simulation study with GROMACS software for a simulation time of 20ns in water environment. Finally, in silico ADMET analysis of the inhibitors using MedChem Designer v3 evaluated the drug likeness of the best hits to be considered for industrial pharmaceutical research.

Malaria resurgence risk in southern Europe: climate assessment in an historically endemic area of rice fields at the Mediterranean shore of Spain.

BackgroundInternational travel and immigration have been related with an increase of imported malaria cases. This fact and climate change, prolonging the period favouring vector development, require an analysis of the malaria transmission resurgence risk in areas of southern Europe. Such a study is made for the first time in Spain. The Ebro Delta historically endemic area was selected due to its rice field landscape, the presence of only one vector, Anopheles atroparvus, with densities similar to those it presented when malaria was present, in a situation which pronouncedly differs from already assessed potential resurgence areas in other Mediterranean countries, such as France and Italy, where many different Anopheles species coexist and a different vector species dominates.MethodsThe transmission risk was assessed analysing: 1) climate diagrams including the minimum temperature for Plasmodium falciparum and Plasmodium vivax development; 2) monthly evolution of the Gradient Model Risk (GMR) index, specifying transmission risk period and number of potential Plasmodium generations; 3) ecological characteristics using remote sensing images with the Eurasia Land Cover characteristics database and the monthly evolution of the Normalized Difference Vegetation Index (NDVI); 4) evaluation of A. atroparvus population dynamics.ResultsClimatological analyses and GMR index show that a transmission risk presently exists, lasting from May until September for P. falciparum, and from May until October for P. vivax. The GMR index shows that the temperature increase does not actually mean a transmission risk increase if accompanied by a precipitation decrease reducing the number of parasite generations and transmission period. Nevertheless, this limitation is offset by the artificial flooding of the rice fields. Maximum NDVI values and A. atroparvus maximum abundance correspond to months with maximum growth of the rice fields.ConclusionsThe Ebro Delta presents the ecological characteristics that favour transmission. The temperature increase has favoured a widening of the monthly potential transmission window with respect to when malaria was endemic. The combined application of modified climate diagrams and GMR index, together with spatial characterization conforms a useful tool for assessing potential areas at risk of malaria resurgence. NDVI is a good marker when dealing with a rice field area.

Monoclonal antibodies AC-43 and AC-29 disrupt Plasmodium vivax development in the Indian malaria vector Anopheles culicifacies (Diptera: culicidae)

A repertoire of monoclonal antibodies (mAbs) was generated against the midgut proteins of Anopheles culicifacies mosquitoes. The mAbs AC-43 and AC-29 significantly inhibited Plasmodium vivax development inside the mosquito midgut. The number of oocysts that developed was reduced by 78.6% when mosquitoes ingested a combination of these two mAbs along with the blood meal. AC-43 mAb binds to the epitope common in 97, 80 and 43 kDa polypeptides from the midgut protein extract, as indicated by western blot analysis. Similarly, the mAb AC-29 recognized 52, 44, 40 and 29 kDa polypeptides. These female midgut-specific polypeptides are shared between An. culicifacies and An. stephensi, two major vectors of malaria in India. Deglycosylation assays revealed that O-linked carbohydrates are the major components in epitopes corresponding to AC-43 and AC-29. Gold particle labelling revealed that both these mAbs preferentially bind to glycoproteins at the apical microvilli and the microvillus-associated network present inside transverse sections of the gut epithelium. These regions are particularly known to have receptors for ookinetes, which enable them to cross this epithelial barrier and provide them with certain necessary chemicals or components for further development into oocysts. Therefore, these glycoproteins appear to be potential candidates for a vector-directed transmission-blocking vaccine (TBV).

Development of Plasmodium vivax in Anopheles superpictus under experimental conditions.

The susceptibility of Anopheles superpictus for Plasmodium vivax was described quantitatively under laboratory conditions. Of the 697 laboratory females studied in 16 groups, 513 (73.5%) females took a bloodmeal, of which 88.4% developed ookinetes on day 1, 56.1% oocysts between days 3 and 11, and 52.5% sporozoites in the salivary gland on days 15 to 63 post-infection. Sporogony was completed in 10-11 days post-infection. There was no difference in the longevity of uninfected and infected females. Infected females survived an average of 30 days (maximum 63 days). Sporozoites survived up to 50 days in the salivary glands without any observable changes in structure and motility. These data indicate that An. superpictus is an efficient laboratory vector of P. vivax and should not be ignored in future entomological field studies.

Development of Plasmodium Vivax in Chemosterilized Anopheline Mosquitoes

Abstract The study was conducted to determine the effect of pupal chemosterilization on the susceptibility of the resulting Anopheles albimanus and A. freeborni mosquitoes to Plasmodium vivax. Mosquitoes were sterilized by exposing pupae for 1, 2 or 4 hours in 1% aqueous solution of the thioaziridine agent, P,P-bis(1-aziridinyl)-N-methyl phosphinothioic amide, ENT-61585. Anopheles albimanus and A. freeborni responded differently to pupal treatment and subsequent adult infection. Virtual complete steriligy of A. albimanus and A. freeborni was obtained after 1- and 4-hour exposure of the respective pupae to the sterilant. The difference in susceptibility between sterilized and normal mosquitoes to the malaria infection was more pronounced in A. albimanus than in A. freeborni. The overall infection rate of treated A. albimanus was significantly reduced over that of the control mosquitoes. In A. freeborni, however, a less marked effect was noticed. The infection in sterilized mosquitoes was not eliminated and sporogony of P. vivax was completed with motile sporozoites in the salivary glands.

Effect of topically applied DDT on development of Plasmodium vivax and P. falciparum in Anopheles quadrimaculatus.

Summary Anopheles quadrimaculatus mosquitoes which had been exposed to infection with Plasmodium vivax or P. falciparum were topically treated with a sub-lethal dose of DDT in acetone. No lethal effect due to the insecticide was evident on the developing parasites. However, surviving mosquitoes were so adversely affected by the DDT that there seemed little chance they would successfully transmit the disease.