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Tropical Medicine and Infectious Disease Nov 2022Intestinal parasitic infections are common infectious diseases causing many health problems and impaired growth and physical development.. Children under five years old... (Review)
Review
Intestinal parasitic infections are common infectious diseases causing many health problems and impaired growth and physical development.. Children under five years old are the most vulnerable to infections, due to their immature immunity and feeding and exploratory behaviours. This systematic review aimed to assess the relationship between intestinal parasitic infections and undernutrition among children under 5 years old. Fifteen studies met the inclusion and exclusion criteria and were classified as high-quality studies. Twelve parasites were reported, including , spp., , , , hookworm, , , spp. and . Ascariasis is the most reported infection, with a prevalence ranging from 10.77% in Ethiopia to 57.14% in Malaysia, and is correlated with stunting (OR 2.17 (95% CI 1.14, 4.13), = 0.02). Giardiasis is the second most reported infection, with a prevalence ranging from 4.43% in Ethiopia to 66.33% in the Central African Republic, and is related to an increased risk of stunting (OR 2.34 (95% CI 1.07, 5.10), = 0.03)), wasting (OR 2.90 (95% CI 1.12, 7.49, = 0.03)), and being underweight (OR 1.53 (95% CI 1.02, 2.29, = 0.04)). The third and fourth most prevalent infections are and hookworm infections. Intestinal parasitic infections can occur very early in life and cause significant growth retardation. It is important to understand the prevalence and effects of infection based on the parasite species in order to implement therapeutic interventions and prevention controls.
PubMed: 36422922
DOI: 10.3390/tropicalmed7110371 -
The American Journal of Tropical... Nov 2020Hookworm is an intestinal parasite that infects nearly 230 million people, with another 5.1 billion at risk, especially in poverty-stricken tropical and subtropical... (Meta-Analysis)
Meta-Analysis
Hookworm is an intestinal parasite that infects nearly 230 million people, with another 5.1 billion at risk, especially in poverty-stricken tropical and subtropical regions. Pregnancy is an especially vulnerable time for hookworm infection because of its effect on both maternal and subsequently fetal health. A systematic review and meta-analysis was conducted. The meta-analysis was performed on the association between maternal hookworm and maternal anemia, as well as maternal hookworm coinfection with malaria. The prevalence of hookworm ranged from 1% to 78% in pregnant women, whereas malaria prevalence ranged from 11% to 81%. Pregnant women with hookworm infection were more likely to have anemia (combined odds ratio [cOR] 2.55 [2.20, 2.96], < 0.001). In addition, pregnant woman with hookworm were more likely to have malaria coinfection (cOR 1.60 [1.38, 1.86], < 0.001). Other effects on maternal and child health were investigated and summarized without systematic review or meta-analysis because of the limited study numbers. Despite current deworming recommendations in pregnant women, heavy hookworm burden, coinfection with malaria, and subsequent anemia persist. Although this is likely due, in part, to a lack of implementation of preventive chemotherapy, additional interventions such as health education, proper waste management, or linking malaria and soil-transmitted helminth treatment and prevention programs may also be needed. Further investigations on maternal-child outcomes as a result of hookworm infection during pregnancy will highlight public health interventional targets to reduce morbidity in pregnant women and children globally.
Topics: Ancylostomatoidea; Anemia; Animals; Cohort Studies; Coinfection; Cross-Sectional Studies; Female; Health Education; Hookworm Infections; Humans; Malaria; Maternal Health; Pregnancy; Pregnancy Complications, Parasitic; Public Health
PubMed: 32840198
DOI: 10.4269/ajtmh.20-0503 -
Impact of hookworm infection and preventive chemotherapy on haemoglobin in non-pregnant populations.Tropical Medicine & International... Dec 2021To assess the impact of hookworm infection and preventive chemotherapy on haemoglobin levels in non-pregnant populations in endemic areas. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To assess the impact of hookworm infection and preventive chemotherapy on haemoglobin levels in non-pregnant populations in endemic areas.
METHOD
Systematic review and meta-analysis searching PubMed and Web of Science for articles published since 2010 reporting either hookworm prevalence and Hb concentration (cross-sectional studies) or Hb concentration before and after the implementation of preventive chemotherapy (before-after studies and randomised controlled trials [RCTs]). For papers published before 2010, data were extracted from a previously published systematic review. Random effects meta-analyses were conducted to examine the relationship between Hb concentration and hookworm infection intensity (from cross-sectional studies) and the effect of preventive chemotherapy on Hb concentration (from before-after studies and RCTs). Sensitivity analyses investigated the impact of malaria endemicity and combined interventions for schistosomiasis and nutrition status on Hb concentration.
RESULTS
Among cross-sectional studies, both light- and heavy-intensity hookworm infections were associated with lower Hb in school-aged children. School-aged children with heavy hookworm infection in settings of high malaria endemicity had lower mean Hb than those in settings of low malaria endemicity. In non-pregnant populations, deworming with albendazole was associated with an increase in Hb of 3.02 g/L (95% CI 0.1, 6.0 g/L). No additional benefit was seen with deworming using albendazole co-administered with praziquantel for schistosomiasis infection or iron supplementation for nutrition status.
CONCLUSION
Our findings confirm the benefits of preventive chemotherapy as a public health intervention.
Topics: Anemia; Anthelmintics; Controlled Before-After Studies; Cross-Sectional Studies; Hemoglobins; Hookworm Infections; Humans; Randomized Controlled Trials as Topic
PubMed: 34587315
DOI: 10.1111/tmi.13681 -
Allergy Apr 2011The rate of increase in prevalence of allergic disease in some countries implies environmental exposures may be important etiological factors. Our aim was to undertake a... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The rate of increase in prevalence of allergic disease in some countries implies environmental exposures may be important etiological factors. Our aim was to undertake a systematic review and meta-analysis of epidemiological studies to quantify the association between current intestinal parasite infection and the presence of atopy and to determine whether this relation is species specific.
METHODS
We searched MEDLINE, EMBASE, LILIACS and CAB Abstracts (to March 2009); reviews; and reference lists from publications. No language restrictions were applied. We included studies that measured current parasite infection using direct fecal microscopy and defined atopy as allergen skin sensitization or presence of specific IgE. We estimated pooled odds ratios (OR) and 95% confidence intervals (95% CI) using data extracted from published papers using random-effects model.
RESULTS
Twenty-one studies met our inclusion criteria. Current parasite infection was associated with a reduced risk of allergen skin sensitization OR 0.69 (95% CI 0.60-0.79; P < 0.01). When we restricted our analyses to current geohelminth infection, the size of effect remained similar OR 0.68 (95% CI 0.60-0.76; P < 0.01). In species-specific analysis, a consistent protective effect was found for infection with Ascaris lumbricoides, Tricuris trichuria, hookworm and Schistosomiasis. There were insufficient data to pool results for atopy defined by the presence of specific IgE.
CONCLUSION
Intestinal parasite infection appears to protect against allergic sensitization. Work should continue to identify the mechanisms of this effect and means of harnessing these to reduce the global burden of allergic disease.
Topics: Dermatitis, Atopic; Humans; Intestinal Diseases, Parasitic
PubMed: 21087217
DOI: 10.1111/j.1398-9995.2010.02512.x -
Tropical Medicine & International... Jul 2010To summarise age- and intensity-stratified associations between human hookworm infection and anaemia and to quantify the impact of treatment with the benzimidazoles,... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
To summarise age- and intensity-stratified associations between human hookworm infection and anaemia and to quantify the impact of treatment with the benzimidazoles, albendazole and mebendazole, on haemoglobin and anaemia in non-pregnant populations.
METHODS
Electronic databases (MEDLINE, EMBASE, PubMed) were searched for relevant studies published between 1980 and 2009, regardless of language, and researchers contacted about potential data. Haemoglobin concentration (Hb) was compared between uninfected individuals and individuals harbouring hookworm infections of different intensities, expressed as standardised mean differences (SMD) and 95% confidence intervals (CI). Meta-analysis of randomised control trials (RCTs) investigated the impact of treatment on Hb and anaemia.
RESULTS
Twenty-three cross-sectional studies, six pre- and post-intervention studies and 14 trials were included. Among cross-sectional studies, moderate- and heavy-intensity hookworm infections were associated with lower Hb in school-aged children, while all levels of infection intensity were associated with lower Hb in adults. Among RCTs using albendazole, impact of treatment corresponded to a 1.89 g/l increase (95%CI: 0.13-3.63) in mean Hb while mebendazole had no impact. There was a positive impact of 2.37 g/l (95%CI: 1.33-3.50) on mean Hb when albendazole was co-administered with praziquantel, but no apparent additional benefit of treatment with benzimidazoles combined with iron supplementation. The mean impact of treatment with benzimidazoles alone on moderate anaemia was small (relative risk (RR) 0.87) with a larger effect when combined with praziquantel (RR 0.61).
CONCLUSIONS
Anaemia is most strongly associated with moderate and heavy hookworm infection. The impact of anthelmintic treatment is greatest when albendazole is co-administered with praziquantel.
Topics: Adolescent; Adult; Aged; Albendazole; Anemia; Anthelmintics; Child; Child, Preschool; Female; Hemoglobins; Hookworm Infections; Humans; Infant; Mebendazole; Middle Aged; Praziquantel; Pregnancy; Research Design
PubMed: 20500563
DOI: 10.1111/j.1365-3156.2010.02542.x -
International Journal of Environmental... Apr 2022Malaria and helminthic co-infection during pregnancy causes fetomaternal haemorrhage and foetal growth retardation. This study determined the pooled burden of pregnancy... (Meta-Analysis)
Meta-Analysis Review
Malaria and helminthic co-infection during pregnancy causes fetomaternal haemorrhage and foetal growth retardation. This study determined the pooled burden of pregnancy malaria and helminthic co-infection in sub-Saharan Africa. CINAHL, EMBASE, Google Scholar, Scopus, PubMed, and Web of Science databases were used to retrieve data from the literature, without restricting language and publication year. The Joanna Briggs Institute's critical appraisal tool for prevalence studies was used for quality assessment. STATA Version 14.0 was used to conduct the meta-analysis. The statistics and Egger's test were used to test heterogeneity and publication bias. The random-effects model was used to estimate the pooled prevalence at a 95% confidence interval (CI). The review protocol has been registered in PROSPERO, with the number CRD42019144812. In total, 24 studies (n = 14,087 participants) were identified in this study. The pooled analysis revealed that 20% of pregnant women were co-infected by malaria and helminths in sub-Saharan Africa. The pooled prevalence of malaria and helminths were 33% and 35%, respectively. The most prevalent helminths were (48%), (37%), and (15%). Significantly higher malaria and helminthic co-infection during pregnancy were observed. Health systems in sub-Saharan Africa must implement home-grown innovative solutions to underpin context-specific policies for the early initiation of effective intermittent preventive therapy.
Topics: Africa South of the Sahara; Coinfection; Female; Helminthiasis; Humans; Malaria; Pregnancy; Pregnant Women; Prevalence
PubMed: 35564842
DOI: 10.3390/ijerph19095444 -
PLoS Medicine Mar 2014Preventive chemotherapy represents a powerful but short-term control strategy for soil-transmitted helminthiasis. Since humans are often re-infected rapidly, long-term... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Preventive chemotherapy represents a powerful but short-term control strategy for soil-transmitted helminthiasis. Since humans are often re-infected rapidly, long-term solutions require improvements in water, sanitation, and hygiene (WASH). The purpose of this study was to quantitatively summarize the relationship between WASH access or practices and soil-transmitted helminth (STH) infection.
METHODS AND FINDINGS
We conducted a systematic review and meta-analysis to examine the associations of improved WASH on infection with STH (Ascaris lumbricoides, Trichuris trichiura, hookworm [Ancylostoma duodenale and Necator americanus], and Strongyloides stercoralis). PubMed, Embase, Web of Science, and LILACS were searched from inception to October 28, 2013 with no language restrictions. Studies were eligible for inclusion if they provided an estimate for the effect of WASH access or practices on STH infection. We assessed the quality of published studies with the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach. A total of 94 studies met our eligibility criteria; five were randomized controlled trials, whilst most others were cross-sectional studies. We used random-effects meta-analyses and analyzed only adjusted estimates to help account for heterogeneity and potential confounding respectively. Use of treated water was associated with lower odds of STH infection (odds ratio [OR] 0.46, 95% CI 0.36-0.60). Piped water access was associated with lower odds of A. lumbricoides (OR 0.40, 95% CI 0.39-0.41) and T. trichiura infection (OR 0.57, 95% CI 0.45-0.72), but not any STH infection (OR 0.93, 95% CI 0.28-3.11). Access to sanitation was associated with decreased likelihood of infection with any STH (OR 0.66, 95% CI 0.57-0.76), T. trichiura (OR 0.61, 95% CI 0.50-0.74), and A. lumbricoides (OR 0.62, 95% CI 0.44-0.88), but not with hookworm infection (OR 0.80, 95% CI 0.61-1.06). Wearing shoes was associated with reduced odds of hookworm infection (OR 0.29, 95% CI 0.18-0.47) and infection with any STH (OR 0.30, 95% CI 0.11-0.83). Handwashing, both before eating (OR 0.38, 95% CI 0.26-0.55) and after defecating (OR 0.45, 95% CI 0.35-0.58), was associated with lower odds of A. lumbricoides infection. Soap use or availability was significantly associated with lower infection with any STH (OR 0.53, 95% CI 0.29-0.98), as was handwashing after defecation (OR 0.47, 95% CI 0.24-0.90). Observational evidence constituted the majority of included literature, which limits any attempt to make causal inferences. Due to underlying heterogeneity across observational studies, the meta-analysis results reflect an average of many potentially distinct effects, not an average of one specific exposure-outcome relationship.
CONCLUSIONS
WASH access and practices are generally associated with reduced odds of STH infection. Pooled estimates from all meta-analyses, except for two, indicated at least a 33% reduction in odds of infection associated with individual WASH practices or access. Although most WASH interventions for STH have focused on sanitation, access to water and hygiene also appear to significantly reduce odds of infection. Overall quality of evidence was low due to the preponderance of observational studies, though recent randomized controlled trials have further underscored the benefit of handwashing interventions. Limited use of the Joint Monitoring Program's standardized water and sanitation definitions in the literature restricted efforts to generalize across studies. While further research is warranted to determine the magnitude of benefit from WASH interventions for STH control, these results call for multi-sectoral, integrated intervention packages that are tailored to social-ecological contexts.
Topics: Adolescent; Adult; Animals; Child; Child, Preschool; Hand Disinfection; Humans; Hygiene; Infant; Infant, Newborn; Nematoda; Nematode Infections; Sanitation; Soil
PubMed: 24667810
DOI: 10.1371/journal.pmed.1001620 -
The Lancet. Infectious Diseases Jun 2013The four common soil-transmitted helminth species-Ascaris lumbricoides, Trichuris trichiura, and the two hookworm species Ancylostoma duodenale and Necator... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The four common soil-transmitted helminth species-Ascaris lumbricoides, Trichuris trichiura, and the two hookworm species Ancylostoma duodenale and Necator americanus-are endemic in South America, but their distribution, infection prevalence, and regional burden are poorly understood. We aimed to estimate the risk and number of people infected with A lumbricoides, T trichiura, and hookworm across South America.
METHODS
We did a systematic review of reports on the prevalence of soil-transmitted helminth infection in South America published up to May 14, 2012. We extracted and georeferenced relevant survey data and did a meta-analysis of the data to assess the geographical distribution of the infection risk with Bayesian geostatistical models. We used advanced Bayesian variable selection to identify environmental determinants that govern the distribution of soil-transmitted helminth infections.
FINDINGS
We screened 4085 scientific papers and identified 174 articles containing relevant survey prevalence data. We georeferenced 6948 survey locations and entered the data into the open-access Global Neglected Tropical Diseases database. Survey data were sparse for the south of the continent and for the western coast, and we identified no relevant information for Uruguay and little data for smaller countries such as Suriname, Guyana, French Guiana, and Ecuador. Population-adjusted prevalence of infection with A lumbricoides was 15·6%, with T trichiura was 12·5%, and with hookworm was 11·9% from 2005 onwards. Risks of contracting soil-transmitted helminth infection have substantially reduced since 2005 (odds ratio 0·47 [95% Bayesian credible interval 0·46-0·47] for A lumbricoides, 0·54 [0·54-0·55] for T trichiura, and 0·58 [0·58-0·59] for hookworm infection).
INTERPRETATION
Our findings offer important baseline support for spatial targeting of soil-transmitted helminthiasis control, and suggest that more information about the prevalence of soil-transmitted helminth infection is needed, especially in countries in which we estimate prevalence of infection to be high but for which current data are scarce.
FUNDING
UBS Optimus Foundation and Brazilian Swiss Joint Research Programme (BSJRP 011008).
Topics: Animals; Helminthiasis; Helminths; Humans; Soil; South America
PubMed: 23562238
DOI: 10.1016/S1473-3099(13)70071-9 -
American Journal of Respiratory and... Sep 2006Epidemiologic studies suggest that intestinal parasite infections may protect against asthma. (Meta-Analysis)
Meta-Analysis Review
RATIONALE
Epidemiologic studies suggest that intestinal parasite infections may protect against asthma.
OBJECTIVES
A systematic review and meta-analysis of epidemiologic studies to determine whether total or species-specific current parasite infection is associated with a reduced risk of asthma or wheeze.
METHODS
We searched MEDLINE, EMBASE, and CINAHL (up to January 2006); reviews; and reference lists from publications, with no language restrictions. We included studies that reported asthma or wheeze as an outcome measure and ascertained parasite infection by fecal examination. We estimated pooled odds ratios (OR) and 95% confidence intervals (CI) using data extracted from published papers, or where available, original data provided by authors, using random effect models.
MEASUREMENTS AND MAIN RESULTS
Thirty-three studies met the inclusion criteria. Infection with any parasite was associated with a small, nonsignificant increase in asthma risk (OR, 1.24; 95% CI, 0.98-1.57; 29 studies). In species-specific analysis, Ascaris lumbricoides was associated with significantly increased odds of asthma (OR, 1.34; 95% CI, 1.05-1.71; 20 studies), while hookworm infection was associated with a significantly strong reduction (OR, 0.50; 95% CI, 0.28-0.90; 9 studies) that was directly and significantly related to infection intensity (p < 0.001; OR for highest tertile of infection, 0.34; 95% CI, 0.19-0.62). Other species had no significant effects on asthma. Infection effects on wheeze were derived from smaller numbers, but revealed a broadly similar pattern of results.
CONCLUSIONS
Parasite infections do not in general protect against asthma, but infection with hookworm may reduce the risk of this disease.
Topics: Adult; Asthma; Child; Humans; Intestinal Diseases, Parasitic; Risk Assessment
PubMed: 16778161
DOI: 10.1164/rccm.200603-331OC -
The Lancet. Microbe Jan 2022The global distribution and morbidity effects for each specific hookworm species is unknown, which prevents implementation of the optimum intervention for local hookworm... (Review)
Review
The global distribution and morbidity effects for each specific hookworm species is unknown, which prevents implementation of the optimum intervention for local hookworm control. We did two systematic reviews of studies on the proportion of hookworm isolates of each species and genus by region of the world and associations between hookworm species-specific infections and morbidity outcomes, particularly severe anaemia. Necator americanus and Ancylostoma spp were present in all regions of the world, although at different ratios. No clear evidence was found for the differential morbidity effects of different hookworm species. Diagnostic methods that differentiate between hookworm species, including molecular methods, need to be developed for widespread use in control programmes to elucidate key features of hookworm epidemiology and control.
Topics: Ancylostoma; Ancylostomatoidea; Animals; Feces; Hookworm Infections; Humans; Morbidity
PubMed: 35544117
DOI: 10.1016/S2666-5247(21)00181-6