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Tropical Medicine & International... Dec 2015To estimate where intermittent preventive treatment (IPTp) using sulphadoxine-pyrimethamine (SP) could be withdrawn as an intervention due to declining malaria... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
To estimate where intermittent preventive treatment (IPTp) using sulphadoxine-pyrimethamine (SP) could be withdrawn as an intervention due to declining malaria transmission intensity, or due to increasing prevalence of the Plasmodium falciparum dihydropteroate synthetase resistance mutation at codon 581G.
METHODS
We conducted a systematic review and meta-analysis of protection against the incidence of low birth weight (LBW) conferred by ≥2 doses of IPTp-SP. We matched these outcomes to a proxy measure of malaria incidence in women of the same studies, applied meta-regression models to these data and conducted sensitivity analysis of the 581G mutation.
RESULTS
Variation in the protective effect of IPTp-SP against LBW could not be explained by malaria transmission intensity. Among primi- and secundigravidae, IPTp-SP protected against LBW where 581G was ≤10.1% [odds ratio (OR): 0.49; 95% confidence intervals (CI): 0.29, 0.81; P = <0.01] and 581G was >10.1% (OR = 0.73; 95% CI: 0.29, 1.81; P = 0.03). Random-effects models among multigravidae showed that IPTp-SP protects against LBW where 581G was ≤10.1% (OR = 0.56; 95% CI: 0.37, 0.86; P = 0.07), a finding of borderline statistical significance. No evidence of protection against LBW was observed where 581G was >10.1% (OR = 0.96; 95% CI: 0.70, 1.34; P = 0.47).
CONCLUSION
There appears to be a prevalence of 581G above which IPTp-SP no longer protects against LBW. Pregnancy studies are urgently needed where 581G is >10.1% to define the specific prevalence threshold where new strategies should be deployed.
Topics: Africa South of the Sahara; Antimalarials; Dihydropteroate Synthase; Drug Combinations; Drug Resistance; Female; Gravidity; Humans; Infant, Low Birth Weight; Malaria, Falciparum; Mutation; Plasmodium falciparum; Pregnancy; Pregnancy Complications, Parasitic; Pyrimethamine; Sulfadoxine
PubMed: 26325263
DOI: 10.1111/tmi.12595 -
Parasites & Vectors Jun 2021Recent studies indicate that the prevalence of non-falciparum malaria, including Plasmodium malariae and Plasmodium ovale spp., is increasing, with some complications in... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Recent studies indicate that the prevalence of non-falciparum malaria, including Plasmodium malariae and Plasmodium ovale spp., is increasing, with some complications in infected individuals. The aim of this review is to provide a better understanding of the malaria prevalence and disease burden due to P. malariae and P. ovale spp.
METHODS
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the Joanna Briggs Institute prevalence study assessment tool were used to select and evaluate the studies, respectively. Six databases: PubMed, WHOLIS, Wiley Library, ScienceDirect, Web of Science and Google Scholar were used to screen articles published during the period January 2000-December 2020. The pooled prevalence estimates for P. malariae and P. ovale spp. were analysed using a random-effects model and the possible sources of heterogeneity were evaluated through subgroup analysis and meta-regression.
RESULTS
Out of the 3297 studies screened, only 113 studies were included; among which 51.33% were from the African Region. The P. malariae and P. ovale spp. pooled prevalence were 2.01% (95% CI 1.31-2.85%) and 0.77% (95% CI 0.50-1.10%) respectively, with the highest prevalence in the African Region. P. malariae was equally distributed among adults (2.13%), children (2.90%) and pregnant women (2.77%) (p = 0.862), whereas P. ovale spp. was more prevalent in pregnant women (2.90%) than in children ≤ 15 years (0.97%) and in patients > 15 years old (0.39%) (p = 0.021). In this review, data analysis revealed that P. malariae and P. ovale spp. have decreased in the last 20 years, but not significantly, and these species were more commonly present with other Plasmodium species as co-infections. No difference in prevalence between symptomatic and asymptomatic patients was observed for either P. malariae or P. ovale spp.
CONCLUSION
Our analysis suggests that knowledge of the worldwide burden of P. malariae and P. ovale spp. is very important for malaria elimination programmes and a particular focus towards improved tools for monitoring transmission for these non-falciparum species should be stressed upon to deal with increased infections in the future.
Topics: Coinfection; Global Health; Humans; Malaria; Plasmodium falciparum; Plasmodium malariae; Plasmodium ovale; Prevalence; Time Factors
PubMed: 34082791
DOI: 10.1186/s13071-021-04797-0 -
Parasites & Vectors Dec 2022The production of Plasmodium gametocytes in vitro is a real challenge. Many protocols have been described, but few have resulted in the production of viable and... (Review)
Review
BACKGROUND
The production of Plasmodium gametocytes in vitro is a real challenge. Many protocols have been described, but few have resulted in the production of viable and infectious gametocytes in sufficient quantities to conduct research on-but not limited to-transmission-blocking drug and vaccine development. The aim of this review was to identify and discuss gametocyte production protocols that have been developed over the last two decades.
METHODS
We analyzed the original gametocyte production protocols published from 2000 onwards based on a literature search and a thorough review. A systematic review was performed of relevant articles identified in the PubMed, Web of Sciences and ScienceDirect databases.
RESULTS
A total 23 studies on the production of Plasmodium gametocytes were identified, 19 involving in vitro Plasmodium falciparum, one involving Plasmodium knowlesi and three involving ex vivo Plasmodium vivax. Of the in vitro studies, 90% used environmental stressors to trigger gametocytogenesis. Mature gametocytemia of up to 4% was reported.
CONCLUSIONS
Several biological parameters contribute to an optimal production in vitro of viable and infectious mature gametocytes. The knowledge gained from this systematic review on the molecular mechanisms involved in gametocytogenesis enables reproducible gametocyte protocols with transgenic parasite lines to be set up. This review highlights the need for additional gametocyte production protocols for Plasmodium species other than P. falciparum.
Topics: Humans; Malaria, Falciparum; Plasmodium falciparum; Plasmodium knowlesi; Plasmodium vivax; Systematic Reviews as Topic
PubMed: 36471426
DOI: 10.1186/s13071-022-05566-3 -
Parasites & Vectors Mar 2023Buffaloes are important contributors to the livestock economy in many countries, particularly in Asia, and tick-borne pathogens (TBPs) commonly infect buffaloes, giving... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Buffaloes are important contributors to the livestock economy in many countries, particularly in Asia, and tick-borne pathogens (TBPs) commonly infect buffaloes, giving rise to serious pathologies other than their zoonotic potential.
METHODS
The present investigation focuses on the prevalence of TBPs infecting buffaloes worldwide. All published global data on TBPs in buffaloes were collected from different databases (e.g., PubMed, Scopus, ScienceDirect, and Google Scholar) and subjected to various meta-analyses using OpenMeta[Analyst] software, and all analyses were conducted based on a 95% confidence interval.
RESULTS
Over 100 articles discussing the prevalence and species diversity of TBPs in buffaloes were retrieved. Most of these reports focused on water buffaloes (Bubalus bubalis), whereas a few reports on TBPs in African buffaloes (Syncerus caffer) had been published. The pooled global prevalence of the apicomplexan parasites Babesia and Theileria, as well as the bacterial pathogens Anaplasma, Coxiella burnetii, Borrelia, Bartonella, and Ehrlichia in addition to Crimean-Congo hemorrhagic fever virus, were all evaluated based on the detection methods and 95% confidence intervals. Interestingly, no Rickettsia spp. were detected in buffaloes with scarce data. TBPs of buffaloes displayed a fairly high species diversity, which underlines the high infection risk to other animals, especially cattle. Babesia bovis, B. bigemina, B. orientalis, B. occultans and B. naoakii, Theileria annulata, T. orientalis complex (orientalis/sergenti/buffeli), T. parva, T. mutans, T. sinensis, T. velifera, T. lestoquardi-like, T. taurotragi, T. sp. (buffalo) and T. ovis, and Anaplasma marginale, A. centrale, A. platys, A. platys-like and "Candidatus Anaplasma boleense" were all were identified from naturally infected buffaloes.
CONCLUSIONS
Several important aspects were highlighted for the status of TBPs, which have serious economic implications for the buffalo as well as cattle industries, particularly in Asian and African countries, which should aid in the development and implementation of prevention and control methods for veterinary care practitioners, and animal owners.
Topics: Animals; Cattle; Anaplasma; Babesiosis; Buffaloes; Cattle Diseases; Prevalence; Rickettsia; Theileria; Tick-Borne Diseases; Ticks
PubMed: 36998029
DOI: 10.1186/s13071-023-05727-y -
Infectious Diseases of Poverty Jul 2020Plasmodium knowlesi is a potential cause of severe and fatal malaria, but comprehensive studies of its pooled prevalence and risk factors are lacking. This study aimed... (Comparative Study)
Comparative Study Meta-Analysis
Prevalence of severe Plasmodium knowlesi infection and risk factors related to severe complications compared with non-severe P. knowlesi and severe P. falciparum malaria: a systematic review and meta-analysis.
BACKGROUND
Plasmodium knowlesi is a potential cause of severe and fatal malaria, but comprehensive studies of its pooled prevalence and risk factors are lacking. This study aimed to explore the prevalence and risk factors related to severe P. knowlesi infection.
METHODS
A systematic review was conducted by retrieving all published articles on severe P. knowlesi available in Web of Science (ISI), Scopus, and PubMed (MEDLINE). Titles, abstracts, and full-text articles were screened, and any irrelevant studies were excluded. The random-effects model was used to compute the pooled prevalence estimate of severe P. knowlesi infection by a metaprop command provided in STATA software. Differences in demographic characteristics, clinical characteristics, and laboratory data were analysed using Review Manager Version 5.3 software for patients in the following groups: 1) patients with severe and non-severe P. knowlesi infection and 2) patients with severe P. knowlesi and severe P. falciparum infection.
RESULTS
Out of the 2382 studies retrieved from the three databases, seven studies with a total enrolment of 1124 patients with P. knowlesi infections were eligible to be included in this systematic review and meta-analysis. The pooled prevalence estimate of severe P. knowlesi infection was 19% (95% CI: 11-27%, I = 93.7%). Severe acute kidney injuries (AKI) (77 cases, 45.6%), jaundice (71 cases, 42%), and hyperparasitaemia (55 cases, 32.5%) were the common clinical manifestations found among patients with severe complications. In comparison to non-severe P. knowlesi infections, patients with severe P. knowlesi infections had significantly higher age, leucocyte count, and parasitaemia levels (P < 0.05). In comparison to patients with severe P. falciparum infections, patients with severe P. knowlesi infections had significantly higher age, neutrophil count, and creatinine levels (P < 0.05).
CONCLUSIONS
This systematic review and meta-analysis demonstrated a high proportion of severe P. knowlesi infections. Patients with severe P. knowlesi infections had higher age, leucocyte count, and parasitaemia levels than those with non-severe P. knowlesi infections. In addition, patients with severe P. knowlesi infections had higher age, neutrophil count, and creatinine levels than those with severe P. falciparum infections.
Topics: Comorbidity; Humans; Malaria; Malaria, Falciparum; Occupations; Parasitemia; Plasmodium falciparum; Plasmodium knowlesi; Prevalence; Risk Factors; Severity of Illness Index
PubMed: 32727617
DOI: 10.1186/s40249-020-00727-x -
International Journal of Environmental... Mar 2022is a non-human parasite that causes zoonotic disease in humans. This systematic review aims to highlight and summarize studies describing human behaviors and activities... (Review)
Review
OBJECTIVES
is a non-human parasite that causes zoonotic disease in humans. This systematic review aims to highlight and summarize studies describing human behaviors and activities that expose humans to mosquito bites. English entries in PubMed, Web of Science, and Science Direct from 2010 to 2020 were systematically perused, and the results were synthesized. Methodological quality was assessed using the Joanna Briggs Institute quality appraisal checklists.
SETTING
Studies that described malaria preventive measures were included. Laboratory, in vivo, in vitro, and animal studies were excluded.
PRIMARY AND SECONDARY OUTCOME MEASURES
The main outcome of the review was findings from studies describing the behavior that exposed a person or a group to infection.
RESULTS
Twelve eligible studies were of good or medium quality. Attitude, disease misconceptions, perceived threat of disease, lack of motivation, and supernatural or traditional beliefs causing individuals to seek treatment from traditional healers influenced the exposure of individuals or communities to malaria. Other factors were forestry activities (2.48, 1.45-4.23,95% CI, = 0.0010) and sleeping outdoors (3.611, 1.48-8.85, 95% CI, = 0.0049).
CONCLUSIONS
Future studies must consider the importance of human behavior and community perspective on the infection to provide novel information to improve the current zoonotic malaria programs. Policymakers should concentrate on understanding human behavior and activities that expose individuals or communities to mosquito bites, in order to better design socially feasible interventions.
Topics: Animals; Humans; Insect Bites and Stings; Malaria; Motivation; Plasmodium knowlesi; Zoonoses
PubMed: 35329359
DOI: 10.3390/ijerph19063675 -
BMC Medicine Jan 2020In endemic areas, pregnant women are highly susceptible to Plasmodium falciparum malaria characterized by the accumulation of parasitized red blood cells (pRBC) in the...
BACKGROUND
In endemic areas, pregnant women are highly susceptible to Plasmodium falciparum malaria characterized by the accumulation of parasitized red blood cells (pRBC) in the placenta. In subsequent pregnancies, women develop protective immunity to pregnancy-associated malaria and this has been hypothesized to be due to the acquisition of antibodies to the parasite variant surface antigen VAR2CSA. In this systematic review we provide the first synthesis of the association between antibodies to pregnancy-specific P. falciparum antigens and pregnancy and birth outcomes.
METHODS
We conducted a systematic review and meta-analysis of population-based studies (published up to 07 June 2019) of pregnant women living in P. falciparum endemic areas that examined antibody responses to pregnancy-specific P. falciparum antigens and outcomes including placental malaria, low birthweight, preterm birth, peripheral parasitaemia, maternal anaemia, and severe malaria.
RESULTS
We searched 6 databases and identified 33 studies (30 from Africa) that met predetermined inclusion and quality criteria: 16 studies contributed estimates in a format enabling inclusion in meta-analysis and 17 were included in narrative form only. Estimates were mostly from cross-sectional data (10 studies) and were heterogeneous in terms of magnitude and direction of effect. Included studies varied in terms of antigens tested, methodology used to measure antibody responses, and epidemiological setting. Antibody responses to pregnancy-specific pRBC and VAR2CSA antigens, measured at delivery, were associated with placental malaria (9 studies) and may therefore represent markers of infection, rather than correlates of protection. Antibody responses to pregnancy-specific pRBC, but not recombinant VAR2CSA antigens, were associated with trends towards protection from low birthweight (5 studies).
CONCLUSIONS
Whilst antibody responses to several antigens were positively associated with the presence of placental and peripheral infections, this review did not identify evidence that any specific antibody response is associated with protection from pregnancy-associated malaria across multiple populations. Further prospective cohort studies using standardized laboratory methods to examine responses to a broad range of antigens in different epidemiological settings and throughout the gestational period, will be necessary to identify and prioritize pregnancy-specific P. falciparum antigens to advance the development of vaccines and serosurveillance tools targeting pregnant women.
Topics: Africa; Cross-Sectional Studies; Erythrocytes; Female; Humans; Infant, Low Birth Weight; Malaria, Falciparum; Placenta; Plasmodium falciparum; Pregnancy; Pregnancy Complications, Parasitic; Pregnancy Outcome
PubMed: 31941488
DOI: 10.1186/s12916-019-1467-6 -
Revista Do Instituto de Medicina... 2022Cryptosporidiosis is a disease caused by the Cryptosporidium spp parasite. As some species of Cryptosporidium have a wide host spectrum, the characterization of the... (Meta-Analysis)
Meta-Analysis
Cryptosporidiosis is a disease caused by the Cryptosporidium spp parasite. As some species of Cryptosporidium have a wide host spectrum, the characterization of the pathogen at the species or genotype level is of great importance to define the sources of infection for humans and the potential for public health. This study investigated the diversity of the genus Cryptosporidium spp. in humans from all over the American continent and observed whether the method used to search for the parasite influenced the prevalence found in the Americas. This systematic review was carried out using the Pubmed, Science direct, Lilacs, Scielo, and Scopus databases with publications from January 1, 2010, to December 31, 2020. For data synthesis, the PRISMA flowchart was used and for the meta-analysis we used the MetaXL program. Of the selected publications, 57, 9 and 16 belonged to the region of South, Central and North America, respectively. The prevalence found for South, Central, and North America was 7%, 7%, and 8%, respectively, when analyzing publications that used only the microscopy method. When we analyzed the publications that used immunological and molecular methods, we found prevalences of 10%, 9%, and 21% for South, Central, and North America, respectively. The C. hominis subtype IbA10G2 was the most reported in the American continent, followed by subtype IeA11G3T3 and, for C. parvum, subtype IIaA15G2RI was the most reported. In conclusion, Cryptosporidium spp. is present throughout the American continent and its prevalence is higher when immunological and/or molecular methods are used, in addition to direct microscopic examination.
Topics: Humans; Cryptosporidiosis; Cryptosporidium; Prevalence; Genotype; Americas; Feces
PubMed: 36383892
DOI: 10.1590/S1678-9946202264070 -
Malaria Journal Dec 2022In the last decade Plasmodium knowlesi has been detected in humans throughout South East Asia. The highest risk groups for this infection are males, adults and those... (Review)
Review
BACKGROUND
In the last decade Plasmodium knowlesi has been detected in humans throughout South East Asia. The highest risk groups for this infection are males, adults and those performing forest-related work. Furthermore, asymptomatic cases of P. knowlesi malaria have been reported including among women and children.
METHODS
Pubmed, Scopus and the Web of Science databases for literature describing asymptomatic P. knowlesi malaria published between 2010 and 2020 were searched. A systematic literature review was conducted to identify studies reporting the prevalence and incidence of laboratory confirmed asymptomatic P. knowlesi cases in humans, their clinical and demographic characteristics, and methods used to diagnose these cases.
RESULTS
By analysing over 102 papers, thirteen were eligible for this review. Asymptomatic P. knowlesi infections have been detected in 0.03%-4.0% of the population depending on region, and infections have been described in children as young as 2 years old. Various different diagnostic methods were used to detect P. knowlesi cases and there were differing definitions of asymptomatic cases in these studies. The literature indicates that regionally-differing immune-related mechanisms may play a part on the prevalence of asymptomatic P. knowlesi.
CONCLUSION
Differing epidemiological characteristics of asymptomatic P. knowlesi malaria in different regions reinforces the need to further investigate disease transmission mechanics. Effective public health responses to changes in P. knowlesi epidemiology require proactive intervention and multisectoral collaboration.
Topics: Child; Humans; Female; Child, Preschool; Plasmodium knowlesi; Communicable Diseases, Emerging
PubMed: 36474243
DOI: 10.1186/s12936-022-04339-8 -
Parasites & Vectors Jan 2017Toxoplasmosis is caused by Toxoplasma gondii which can infect all warm-blooded animals. As the most common feline definitive host, cats play a vital role in the... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Toxoplasmosis is caused by Toxoplasma gondii which can infect all warm-blooded animals. As the most common feline definitive host, cats play a vital role in the transmission of T. gondii. However, national estimates of the seroprevalence of T. gondii in cats in mainland China are lacking, and therefore a systematic review and meta-analysis were performed to provide insight into national environmental transmission levels and potential transmission to humans.
METHODS
Studies published up until July 1, 2016, on T. gondii seroprevalence in cats within mainland China were searched for in CNKI, WanFang, CBM, PubMed, Embase and through the reference lists of resulting articles. The seroprevalence with its 95% confidence interval (CI) for each individual study was presented, and then point estimates and their 95% confidence intervals (CIs) of pooled seroprevalence were calculated. Subgroup analyses were performed according to potential risk factors.
RESULTS
A total of 38 eligible studies, published between 1995 to 2016, covering fifteen provinces and municipalities, and involving 7,285 cats, were included. The seroprevalence in cats per study ranged from 3.9 to 79.4% with a median of 20.3%. As substantial heterogeneity existed among studies, a random-effects model was used to estimate the pooled seroprevalence. The value of the point estimate seroprevalence was 24.5% (95% CI: 20.1-29.0). Seroprevalence in stray cats was significantly higher than in pet cats (OR = 3.00, 95% CI: 1.60-5.64). The seroprevalence increased significantly with cat age (P = 0.018) with 17.4% (95% CI: 7.6-27.2) in the group of ≤ 1 year old, 19.5% (95% CI: 12.7-26.3) in the group of ≤ 3 year-old and 31.6% (95% CI: 22.9-40.3) in the group of > 3 year-old.
CONCLUSIONS
The seroprevalence of T. gondii in cats in mainland China was moderate and was associated with cat ownership and age. Due to the increasing prevalence of pet cats in China and the intimate relationship between these cats and humans, this might present a significant exposure risk, particularly for China's large susceptible population. Therefore, further research is needed into the links between cat ownership and human T. gondii infection and how to reduce T. gondii exposure in humans via cat contacts and the environmental contamination with T. gondii oocysts by cats.
Topics: Animals; Antibodies, Protozoan; Cat Diseases; Cats; China; Disease Transmission, Infectious; Humans; Risk Assessment; Seroepidemiologic Studies; Toxoplasma; Toxoplasmosis, Animal; Zoonoses
PubMed: 28086987
DOI: 10.1186/s13071-017-1970-6