Genome-wide in silico analysis for novel regulators of gametocyte development critical for transmission of Plasmodium falciparum

@#Malaria, caused by the unicellular Apicomplexan protozoa of the genus Plasmodium, is an infectious disease transmitted via female Anopheles mosquitoes. The sexual stage (gametocytes) of malaria parasites is the key to the transmission of parasites from vertebrate hosts to mosquitoes, representing critical bottleneck of the parasite life cycle. This study has established a systematic computational pipeline to achieve the genome-wide in silico analysis and find 708 novels potentially indispensable genes for gametocyte development, consisting of 644 protein coding genes, 56 ncRNA genes and 8 pseudogenes, with a total of 191 genes in the transmembrane, 29 protein coding genes to be exported proteins, and 58 genes in apicoplast regions. Furthermore, Gene Ontology analysis showed that the largest cluster was cellular processes with nucleus and cytosol highest, followed by molecular function with binding and oxidoreductase activities abundant. Meanwhile, when a text searched, using PlasmoDB, there were 300 genes with annotations of “putative”, and 196 genes with annotations of “unknown function”. These data would be helpful to provide potential targets for effective malaria transmission-blocking strategies.

Prevalence of P. falciparum Gametocyte Carrying between Two Sympatric Ethnic Groups Living in Seasonal Malaria Transmission Setting of Burkina Faso after Universal Bed Nets Coverage Campaigns

Aims: This study aimed to compare the prevalence of P. falciparumgametocyte carriage in two sympatric ethnic groups living in seasonal malaria transmission setting in Burkina Faso.Study Design: A cross-sectional survey was conducted from September to November 2017 in children aged from 2 to 12 years and living in Barkoundouba, avillage located at the Northeast part of Ouagadougou, capital city of Burkina Faso. The study participants were subject to clinical examination including axillary temperature. Blood samples were collected from finger pricks to performed RDT and blood smears for malaria diagnosis and on filter paper for molecular detection of the parasite. Any case of fever (temperature ≥ 37.5°C) with RDT positive was treated according to national guideline.Methodology:We included 461 patients in this study. P. falciparumpresence and densities were determined by microscopy using Giemsa-stained thick blood smears. The nested PCR was used toconfirm the presence of the asexual parasites assessed by the microscopy. Results: P. falciparumprevalence assessed by microscopy was 83 (32.55%) and 103 (50%) for Fulani and Mossirespectively,whereas the prevalence by nested PCR was 88 (39.11%) for Fulani and 121 (68.75%) for Mossi. The gametocyte carriage in the two ethnic groups was: 3.53% for Fulani and 11.65% for Mossi. The prevalence ratio for P. falciparumasymptomatic and gametocyte carriers was 1.5 and 3 in favor of Mossi group respectively.Conclusion:This study showed that the Fulani have a lower prevalence of P. falciparumcompared to the Mossi group despite the decrease of parasitemia and prevalence in both groups compared to previous studies

Cloning,expression and identification of gametocyte specific protein Pfgdv1 of Plasmodium falciparum / 中国血吸虫病防治杂志

Objective To clone a gametocyte specific protein Pfgdv1 of Plasmodium falciparum,express and identify re?combinant Pfgdv1 protein in vitro. Methods PCR was performed to amplify Pfgdv1 from P. falciparum DNA which was got from the patient who was infected with P. falciparum,and the PCR product was inserted into pET28a(+)vector. pET28a?Pfg?dv1 recombinant plasmid was constructed and transformed into E. coli host BL21(DE3+). IPTG was used to induce the recombi?nant Pfgdv1 protein fused with His tag,and the protein was purified by His?NTA affinity chromatography. The recombinant pro?tein was identified by SDS?PAGE and Western blotting. Results The PCR product of Pfgdv1 gene was about 1.65 kb,meeting the expectation of predicted fragment size. The recombinant protein was about 67 kDa,which could be recognized by His?Tag monoclonal antibody. Conclusion The Pfgdv1 gene of P. falciparum is successfully cloned,and the recombinant Pfgdv1 pro?tein is expressed,thereby providing an opportunity for further study on transmission blocking vaccine.

Primer informe de hepatozoonosis en un perro de Tamaulipas, México / First report of hepatozoonsis in a dog from Tamaulipas, Mexico

A 3-year-old male Bloodhound dog was presented to a private veterinary hospital at Ciudad Victoria, Tamaulipas, Mexico, with a 2-week history of weight loss, generalized weakness, anorexia and ptyalism. Results of a hemogram revealed moderate anemia with a chronic inflammatory leukogram. Also, various neutrophlis (approximately 10%) containing elongated pale blue staining intracytoplasmic inclusions, compatible with gametocytes of Hepatozoon spp were observed. Up until now, this is the first case report of canine hepatozoonosis detected in Tamaulipas.

Un perro Bloodhound macho de 3 años de edad fue remitido a una clínica particular de Ciudad Victoria, Tamaulipas, México, con historia de pérdida de peso, debilidad generalizada, anorexia y ptialismo de 2 semanas de evolución. Los resultados del hemograma revelaron una anemia moderada y leucograma con inflamación crónica. Además, se observó que 10% de neutrófilos contenían en su citoplasma pequeñas estructuras de forma alongada de color azul pálido, compatibles con gametocitos de Hepatozoon spp. Hasta ahora, éste es el primer caso de hepatozoonosis canina detectada en Tamaulipas.

Plasmodium falciparum gametocyte carriage, sex ratios and asexual parasite rates in Nigerian children before and after a treatment protocol policy change instituting the use of artemisinin-based combination therapies

The effects of artemisinin-based combination therapies (ACTs) on transmission of Plasmodium falciparum were evaluated after a policy change instituting the use of ACTs in an endemic area. P. falciparum gametocyte carriage, sex ratios and inbreeding rates were examined in 2,585 children at presentation with acute falciparum malaria during a 10-year period from 2001-2010. Asexual parasite rates were also evaluated from 2003-2010 in 10,615 children before and after the policy change. Gametocyte carriage declined significantly from 12.4 percent in 2001 to 3.6 percent in 2010 (@@χ2 for trend = 44.3, p < 0.0001), but sex ratios and inbreeding rates remained unchanged. Additionally, overall parasite rates remained unchanged before and after the policy change (47.2 percent vs. 45.4 percent), but these rates declined significantly from 2003-2010 (@@χ2 for trend 35.4, p < 0.0001). Chloroquine (CQ) and artemether-lumefantrine (AL) were used as prototype drugs before and after the policy change, respectively. AL significantly shortened the duration of male gametocyte carriage in individual patients after treatment began compared with CQ (log rank statistic = 7.92, p = 0.005). ACTs reduced the rate of gametocyte carriage in children with acute falciparum infections at presentation and shortened the duration of male gametocyte carriage after treatment. However, parasite population sex ratios, inbreeding rates and overall parasite rate were unaffected.

Parasitemia Characteristics of Plasmodium vivax Malaria Patients in the Republic of Korea

Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/microL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/microL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.

Parasitemia Characteristics of Plasmodium vivax Malaria Patients in the Republic of Korea

Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/microL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/microL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.

Some features of primary and recrudescent amodiaquine-resistant Plasmodium falciparum infections in Nigerian children

Characteristics of primary and recrudescent Plasmodium falciparum infections were evaluated in 25 children who did not recover after amodiaquine (AQ) treatment. Recrudescence was detected by a thick blood smear and confirmed by polymerase chain reaction. Over half of recrudescent events occurred after 14 days of initiation of treatment and were associated with relatively low asexual parasitaemia. We examined the gametocyte sex ratio (GSR) in these children and in age and gender-matched controls that had AQ-sensitive (AQ-S) infections (n = 50). In both AQ-S and AQ-resistant (AQ-R) infections, the GSR was female-biased pre-treatment and became male-biased by the third day after treatment initiation. However, gametocyte males persisted after this period in children with AQ-R infections. AQ-recrudescent infections are relatively low (25 of 612.4 percent) in children from this endemic area.

Gametocyte Clearance in Uncomplicated and Severe Plasmodium falciparum Malaria after Artesunate-Mefloquine Treatment in Thailand

Artemisinin-based combination therapy (ACT) is currently promoted as a strategy for treating both uncomplicated and severe falciparum malaria, targeting asexual blood-stage Plasmodium falciparum parasites. However, the effect of ACT on sexual-stage parasites remains controversial. To determine the clearance of sexual-stage P. falciparum parasites from 342 uncomplicated, and 217 severe, adult malaria cases, we reviewed and followed peripheral blood sexualstage parasites for 4 wk after starting ACT. All patients presented with both asexual and sexual stage parasites on admission, and were treated with artesunate-mefloquine as the standard regimen. The results showed that all patients were asymptomatic and negative for asexual forms before discharge from hospital. The percentages of uncomplicated malaria patients positive for gametocytes on days 3, 7, 14, 21, and 28 were 41.5, 13.1, 3.8, 2.0, and 2.0%, while the percentages of gametocyte positive severe malaria patients on days 3, 7, 14, 21, and 28 were 33.6, 8.2, 2.7, 0.9, and 0.9%, respectively. Although all patients were negative for asexual parasites by day 7 after completion of the artesunate-mefloquine course, gametocytemia persisted in some patients. Thus, a gametocytocidal drug, e.g., primaquine, may be useful in combination with an artesunate-mefloquine regimen to clear gametocytes, so blocking transmission more effectively than artesunate alone, in malaria transmission areas.

The study of the effective mechanism of infected host serum on the infectivity of gametocytes of Plasmodium yoelii (P.yoelii) / 中国免疫学杂志

Objective:To clarify the mechanism of crisis serum' mediated gametocyte infectivity to the mosquito vector Methods:Observing the effects of mouse serum , which was obtained 5 days after P yoelii infection (D5 serum) on gametocyte infectivity by IFA and mosquito live feeds, and the production of IFN ??TNF ??IL 4 and NO - 2 in the hosts in vivo and in vitro by ELISA and Griess reaction And to investigate the ability of malaria parasitized red blood cell extract (PRBC extract) to induce NO Results:The development of the gametocytes from mice 5 days postinfection into ookinetes were completely inhibited D5 serum was not immediate to inhibit gametocyte development, which was injected intravenously into the mice 3 days after P yoelii infection But 4 h later after injection D5 serum stimulated the increasing IFN ? and NO production and inhibited gametocyte infectivity Moreover, PRBC extract showed the ability to induce NO Conclusion:Infected host serum blocks transmission of P yoelii via a nitric oxide dependent mechanism