scholarly journals Impact of an Irrigation Dam on the Transmission and Diversity of Plasmodium falciparum in a Seasonal Malaria Transmission Area of Northern Ghana

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Eric Kyei-Baafour ◽  
Bernard Tornyigah ◽  
Benjamin Buade ◽  
Langbong Bimi ◽  
Abraham R. Oduro ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Parasite Density ◽  
Parasite Prevalence ◽  
Dry Season ◽  
Water Bodies ◽  
Northern Ghana ◽  
Wet Season ◽  
Transmission Area ◽  
Dam Site

Water bodies such as dams are known to alter the local transmission patterns of a number of infectious diseases, especially those transmitted by insects and other arthropod vectors. The impact of an irrigation dam on submicroscopic asexual parasite carriage in individuals living in a seasonal malaria transmission area of northern Ghana was investigated. A total of 288 archived DNA samples from two cross-sectional surveys in two communities in the Bongo District of Northern Ghana were analysed. Parasite density was determined by light microscopy and PCR, and parasite diversity was assessed by genotyping of the polymorphic Plasmodium falciparum msp2 block-3 region. Submicroscopic parasitaemia was estimated as the proportional difference between positive samples identified by PCR and microscopy. Dry season submicroscopic parasite prevalence was significantly higher (71.0%, p=0.013) at the dam site compared with the nondam site (49.2%). Similarly, wet season submicroscopic parasite prevalence was significantly higher at the dam site (54.5%, p=0.008) compared with the nondam site (33.0%). There was no difference in parasite density between sites in the dry season (p=0.90) and in the wet season (p=0.85). Multiplicity of infection (MOI) based on PCR data was significantly higher at the dam site compared with the nondam site during the dry season (p<0.0001) but similar between sites during the wet season. MOI at the nondam site was significantly higher in the wet season than in the dry season (2.49, 1.26, p<0.0001) but similar between seasons at the dam site. Multivariate analysis showed higher odds of carrying submicroscopic parasites at the dam site in both dry season (OR = 7.46, 95% CI = 3.07–18.15) and in wet season (OR = 1.73, 95% CI = 1.04–2.86). The study findings suggest that large water bodies impact year-round carriage of submicroscopic parasites and sustain Plasmodium transmission.

scholarly journals Plasmodium falciparum increases its investment in gametocytes in the wet season in asymptomatic individuals

2020 ◽  
Author(s):  
Colins O. Oduma ◽  
Sidney Ogolla ◽  
Harrysone Atieli ◽  
Bartholomew N. Ondigo ◽  
Ming-Chieh Lee ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Parasite Prevalence ◽  
Dry Season ◽  
Wet Season ◽  
Western Kenya ◽  
Gametocyte Carriage ◽  
Vector Abundance ◽  
Asymptomatic Individuals

AbstractIn many regions, malaria transmission is seasonal, but it is not well understood whether P. falciparum modulates its investment in transmission in response to seasonal vector abundance. In two sites in western Kenya (Chulaimbo and Homa Bay), we sampled 1116 asymptomatic individuals in the wet season, when vectors are abundant, and 1743 in the dry season. We screened for P. falciparum by qPCR, and gametocytes by pfs25 RT-qPCR. Parasite prevalence in Chulaimbo and Homa Bay was 27.1% and 9.4% in the dry season, and 48.2% and 7.8% in the wet season respectively. Mean parasite densities did not differ between seasons (P=0.562). A contrasting pattern of gametocyte carriage was observed. In the wet season, fewer infections harbored gametocytes (22.3% vs. 33.8%, P=0.009), but densities were 3-fold higher (P<0.001). Thus, in the wet season, among gametocyte positive individuals, higher proportion of all parasites were gametocytes, reflecting an increased investment in transmission.

scholarly journals Increased investment in gametocytes in asymptomatic Plasmodium falciparum infections in the wet season

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Colins O. Oduma ◽  
Sidney Ogolla ◽  
Harrysone Atieli ◽  
Bartholomew N. Ondigo ◽  
Ming-Chieh Lee ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Limit Of Detection ◽  
Parasite Prevalence ◽  
Dry Season ◽  
Control Measures ◽  
Wet Season ◽  
Western Kenya ◽  
Vector Abundance ◽  
Asymptomatic Infections ◽  
Asymptomatic Individuals

Abstract Background Transmission stemming from asymptomatic infections is increasingly being recognized as a threat to malaria elimination. In many regions, malaria transmission is seasonal. It is not well understood whether Plasmodium falciparum modulates its investment in transmission to coincide with seasonal vector abundance. Methods We sampled 1116 asymptomatic individuals in the wet season, when vectors are abundant, and 1743 in the dry season, in two sites in western Kenya, representing different transmission intensities (Chulaimbo, moderate transmission, and Homa Bay, low transmission). Blood samples were screened for P. falciparum by qPCR, and gametocytes by pfs25 RT-qPCR. Results Parasite prevalence by qPCR was 27.1% (Chulaimbo, dry), 48.2% (Chulaimbo, wet), 9.4% (Homabay, dry), and 7.8% (Homabay, wet). Mean parasite densities did not differ between seasons (P = 0.562). pfs25 transcripts were detected in 119/456 (26.1%) of infections. In the wet season, fewer infections harbored detectable gametocytes (22.3% vs. 33.8%, P = 0.009), but densities were 3-fold higher (wet: 3.46 transcripts/uL, dry: 1.05 transcripts/uL, P < 0.001). In the dry season, 4.0% of infections carried gametocytes at moderate-to-high densities likely infective (> 1 gametocyte per 2 uL blood), compared to 7.9% in the wet season. Children aged 5–15 years harbored 76.7% of infections with gametocytes at moderate-to-high densities. Conclusions Parasites increase their investment in transmission in the wet season, reflected by higher gametocyte densities. Despite increased gametocyte densities, parasite density remained similar across seasons and were often below the limit of detection of microscopy or rapid diagnostic test, thus a large proportion of infective infections would escape population screening in the wet season. Seasonal changes of gametocytemia in asymptomatic infections need to be considered when designing malaria control measures.

Population dynamics of Plasmodium falciparum in an unstable malaria area of eastern Sudan

Parasitology ◽  
2000 ◽  
Vol 120 (2) ◽  
pp. 105-111 ◽  
Author(s):  
H. A. BABIKER ◽  
A. A. ABDEL-MUHSIN ◽  
A. HAMAD ◽  
M. J. MACKINNON ◽  
W. G. HILL ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Population Dynamics ◽  
Malaria Transmission ◽  
Dry Season ◽  
Allele Frequencies ◽  
Wet Season ◽  
Transmission Season ◽  
Large Repertoire ◽  
Eastern Sudan

The Plasmodium falciparum population in Asar village, eastern Sudan, where malaria transmission is markedly seasonal, was monitored monthly over a period of 15 months. A cohort of infected patients was treated and then followed monthly throughout the dry season until the next transmission season. Parasitaemia detected by microscopy among the cohort reduced dramatically following treatment, but remained sporadic during the dry season, and reappeared following the onset of the next wet season. However between 40 and 50% of the cohort retained a persisting parasitaemia detectable by PCR throughout the dry season. These parasites were genetically complex, consisting of multiple clones with a large repertoire of alleles of the studied genes. While the number of clones per host dropped significantly following treatment of acute cases during the transmission season, drug treated people nevertheless maintained an average of one clone throughout the dry season. Allele frequencies of MSP-1, MSP-2 and GLURP showed slight, statistically insignificant, fluctuations between the dry and wet seasons. A higher frequency of inbreeding was estimated among the parasites that survived the dry season compared to the wet season.

scholarly journals Large-Scale Surveillance of Plasmodium falciparum crt(K76T) in Northern Ghana

2007 ◽  
Vol 51 (9) ◽  
pp. 3407-3409 ◽  
Author(s):  
Stephan Ehrhardt ◽  
Teunis A. Eggelte ◽  
Sarah Kaiser ◽  
Lydia Adjei ◽  
Gerd D. Burchard ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Combination Therapy ◽  
Life Span ◽  
Large Scale ◽  
Artemisinin Combination Therapy ◽  
Dry Season ◽  
Chloroquine Resistance ◽  
Northern Ghana ◽  
Resistance Marker

ABSTRACT Surveillance of Plasmodium falciparum crt(K76T) [Pfcrt(K76T)], a resistance marker of chloroquine and, limitedly, amodiaquine, in >4,000 children in northern Ghana revealed a prevalence of 79%. Pfcrt(K76T) was heterogeneously distributed and associated with chloroquine use, low parasitemia, and the dry season. Widespread chloroquine resistance challenges the regional life span of amodiaquine as a partner drug in artemisinin combination therapy.

scholarly journals Effect of Seasonality and Ecological Factors on the Prevalence of the Four Malaria Parasite Species in Northern Mali

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Ousmane A. Koita ◽  
Lansana Sangaré ◽  
Hammadoun A. Sango ◽  
Sounkalo Dao ◽  
Naffet Keita ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Parasite ◽  
Parasite Species ◽  
Ecological Factors ◽  
Seasonal Fluctuation ◽  
Parasite Prevalence ◽  
Dry Season ◽  
Sahara Desert ◽  
Cross Sectional ◽  
Hot Dry Season

Background. We performed 2 cross-sectional studies in Ménaka in the Northeastern Mali across 9 sites in different ecological settings: 4 sites have permanent ponds, 4 without ponds, and one (City of Ménaka) has a semipermanent pond. We enrolled 1328 subjects in May 2004 (hot dry season) and 1422 in February 2005 (cold dry season) after the rainy season.Objective.To examine the seasonality of malaria parasite prevalence in this dry northern part of Mali at the edge of the Sahara desert.Results. Slide prevalence was lower in hot dry than cold dry season (4.94 versus 6.85%,P=0.025). Gametocyte rate increased to 0.91% in February. Four species were identified.Plasmodium falciparumwas most prevalent (74.13 and 63.72%).P. malariaeincreased from 9.38% to 22.54% in February. In contrast, prevalence ofP. vivaxwas higher (10.31%) without seasonal variation. Smear positivity was associated with splenomegaly (P=0.007). Malaria remained stable in the villages with ponds (P=0.221); in contrast, prevalence varied between the 2 seasons in the villages without ponds (P=0.004).Conclusion. Malaria was mesoendemic; 4 species circulates with a seasonal fluctuation forPlasmodium falciparum.

scholarly journals Variation of prevalence of malaria, parasite density and the multiplicity of Plasmodium falciparum infection throughout the year at three different health centers in Brazzaville, Republic of Congo

2020 ◽  
Author(s):  
- PEMBE ISSAMOU MAYENGUE ◽  
Dezi Kouhounina Batsimba ◽  
Roch Fabien Niama ◽  
Reyna Ibara Ottia ◽  
Alida Malonga-Massanga ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Parasite Density ◽  
Santé Publique ◽  
Falciparum Infection ◽  
P Value ◽  
Multiplicity Of Infection ◽  
Different Seasons ◽  
Dry Seasons ◽  
Sante Publique

Abstract Background: In the Republic of Congo, hot temperature and seasons distortions observed may impact the development of malaria parasites. We investigate the variation of malaria cases, parasite density and the multiplicity of Plasmodium falciparum infection throughout the year in Brazzaville. Methods: From May 2015 to May 2016, suspected patients with uncomplicated malaria were enrolled at the Hôpital de Mfilou, CSI « Maman Mboualé», and the Laboratoire National de Santé Publique. For each patient, thick blood was examined and parasite density was calculated. After DNA isolation, MSP1 and MSP2 genes were genotyped.Results : A total of 416, 259 and 131 patients with suspected malaria were enrolled at the CSI «Maman Mboualé», Hôpital de Mfilou and the Laboratoire National de Santé Publique respectively. Proportion of malaria cases and geometric mean parasite density were higher at the CSI «Maman Mboualé» compared to over sites (P-value ˂0.001). However the multiplicity of infection was higher at the Hôpital de Mfilou ( P-value ˂0.001). At the Laboratoire National de Santé Publique, malaria cases and multiplicity of infection were not influenced by different seasons. However, variation of the mean parasite density was statistically significant ( P-value ˂0.01). Higher proportions of malaria cases were found at the end of main rainy season either the beginning of the main dry season at the Hôpital de Mfilou and the CSI «Maman Mboualé»; while, lowest proportions were observed in September and January and in September and March respectively. Higher mean parasite densities were found at the end of rainy seasons with persistence at the beginning of dry seasons. Lowest mean parasite densities were found during dry seasons, with persistence at the beginning of rainy seasons. Fluctuation of the multiplicity of infection throughout the year was observed without significance between seasons.Conclusion: The current study suggests that malaria transmission is still variable between the north and south parts of Brazzaville. Seasonal fluctuations of malaria cases and mean parasite densities were observed with some extension to different seasons. Thus, both meteorological and entomological studies are needed to update the season’s periods as well as malaria transmission intensity in Brazzaville.

scholarly journals The Diversity, Multiplicity of Infection and Population Structure of P. falciparum Parasites Circulating in Asymptomatic Carriers Living in High and Low Malaria Transmission Settings of Ghana

Genes ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 434 ◽  
Author(s):  
Zakaria Abukari ◽  
Ruth Okonu ◽  
Samuel B. Nyarko ◽  
Aminata C. Lo ◽  
Cheikh C. Dieng ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Population Structure ◽  
Malaria Transmission ◽  
Parasite Prevalence ◽  
Transmission Intensity ◽  
Multiplicity Of Infection ◽  
Malaria Transmission Intensity ◽  
Ms Analysis ◽  
Greater Accra Region ◽  
Low Malaria Transmission

Background: Diversity in Plasmodium falciparum poses a major threat to malaria control and elimination interventions. This study utilized 12 polymorphic microsatellite (MS) markers and the Msp2 marker to examine diversity, multiplicity of infection (MOI) as well as the population structure of parasites circulating in two sites separated by about 92 km and with varying malaria transmission intensities within the Greater Accra Region of Ghana. Methods: The diversity and MOI of P. falciparum parasites in 160 non-symptomatic volunteers living in Obom (high malaria transmission intensity) and Asutsuare (low malaria transmission intensity) aged between 8 and 60 years was determined using Msp2 genotyping and microsatellite analysis. Results: The prevalence of asymptomatic P. falciparum carriers as well as the parasite density of infections was significantly higher in Obom than in Asutsuare. Samples from Asutsuare and Obom were 100% and 65% clonal, respectively, by Msp2 genotyping but decreased to 50% and 5%, respectively, when determined by MS analysis. The genetic composition of parasites from Obom and Asutsuare were highly distinct, with parasites from Obom being more diverse than those from Asutsuare. Conclusion: Plasmodium falciparum parasites circulating in Obom are genetically more diverse and distinct from those circulating in Asutsuare. The MOI in samples from both Obom and Asutsuare increased when assessed by MS analysis relative to MSP2 genotyping. The TA40 and TA87 loci are useful markers for estimating MOI in high and low parasite prevalence settings.

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