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Advances in Parasitology 2004The scientific study of human hookworm infection began at the dawn of the twentieth century. In recent years, there have been dramatic improvements in our understanding... (Review)
Review
The scientific study of human hookworm infection began at the dawn of the twentieth century. In recent years, there have been dramatic improvements in our understanding of many aspects of this globally widespread parasite. This chapter reviews recent advances in our understanding in the biology, immunology, epidemiology, public health significance and control of hookworm, and to look forward to the study of this important parasite in the 21st century. Advances in molecular biology has lead to the identification of a variety of new molecules from hookworms, which have importance either in the molecular pathogenesis of hookworm infection or in the host-parasite relationship; some are also promising vaccine targets. At present, relatively little is known about the immune responses to hookworm infection, although it has recently been speculated that hookworm and other helminths may modulate specific immune responses to other pathogens and vaccines. Our epidemiological understanding of hookworm has improved through the development of mathematical models of transmission dynamics, which coupled with decades of field research across multiple epidemiological settings, have shown that certain population characteristics can now be recognised as common to the epidemiology, population biology and control of hookworm and other helminth species. Recent recognition of the subtle, but significant, impact of hookworm on health and education, together with the simplicity, safety, low cost and efficacy of chemotherapy has spurred international efforts to control the morbidity due to infection. Large-scale treatment programmes are currently underway, ideally supported by health education and integrated with the provision of improved water and sanitation. There are also on-going efforts to develop novel anthelmintic drugs and anti-hookworm vaccines.
Topics: Ancylostomatoidea; Animals; Cost of Illness; History, 21st Century; Hookworm Infections; Humans; Intestinal Diseases, Parasitic
PubMed: 15603764
DOI: 10.1016/S0065-308X(04)58004-1 -
PLoS Neglected Tropical Diseases Sep 2008Hookworm infection is among the major causes of anaemia in poor communities, but its importance in causing maternal anaemia is poorly understood, and this has hampered... (Review)
Review
BACKGROUND AND OBJECTIVES
Hookworm infection is among the major causes of anaemia in poor communities, but its importance in causing maternal anaemia is poorly understood, and this has hampered effective lobbying for the inclusion of anthelmintic treatment in maternal health packages. We sought to review existing evidence on the role of hookworm as a risk factor for anaemia among pregnant women. We also estimate the number of hookworm infections in pregnant women in sub-Saharan Africa (SSA).
METHODS
Structured searches using MEDLINE and EMBASE as well as manual searches of reference lists were conducted, and unpublished data were obtained by contacting authors. Papers were independently reviewed by two authors, and relevant data were extracted. We compared haemoglobin concentration (Hb) according to intensity of hookworm infection and calculated standardised mean differences and 95% confidence intervals. To estimate the number of pregnant women, we used population surfaces and a spatial model of hookworm prevalence.
FINDINGS
One hundred and five reports were screened and 19 were eligible for inclusion: 13 cross-sectional studies, 2 randomised controlled trials, 2 non-randomised treatment trials and 2 observational studies. Comparing uninfected women and women lightly (1-1,999 eggs/gram [epg]) infected with hookworm, the standardised mean difference (SMD) was -0.24 (95% CI: -0.36 to -0.13). The SMD between women heavily (4000+ epg) infected and those lightly infected was -0.57 (95% CI: -0.87 to -0.26). All identified intervention studies showed a benefit of deworming for maternal or child health, but since a variety of outcomes measures were employed, quantitative evaluation was not possible. We estimate that 37.7 million women of reproductive age in SSA are infected with hookworm in 2005 and that approximately 6.9 million pregnant women are infected.
CONCLUSIONS
Evidence indicates that increasing hookworm infection intensity is associated with lower haemoglobin levels in pregnant women in poor countries. There are insufficient data to quantify the benefits of deworming, and further studies are warranted. Given that between a quarter and a third of pregnant women in SSA are infected with hookworm and at risk of preventable hookworm-related anaemia, efforts should be made to increase the coverage of anthelmintic treatment among pregnant women.
Topics: Africa South of the Sahara; Ancylostomatoidea; Anemia; Animals; Ecosystem; Female; Geography; Hookworm Infections; Humans; Pregnancy; Pregnancy Complications; Risk Factors
PubMed: 18820740
DOI: 10.1371/journal.pntd.0000291 -
PloS One 2018Anemia in pregnancy is a major public health concern worldwide, especially in developing countries. Thus, there is a need of having current information and local data on...
Anemia and its association with coffee consumption and hookworm infection among pregnant women attending antenatal care at Debre Markos Referral Hospital, Northwest Ethiopia.
BACKGROUND
Anemia in pregnancy is a major public health concern worldwide, especially in developing countries. Thus, there is a need of having current information and local data on the prevalence of anemia and associated factors during pregnancy to help inform preventive programmes. The aim of this study was to assess the prevalence of anemia and associated factors among pregnant women attending antenatal care at Debre Markos Referral Hospital, Northwest Ethiopia.
METHODS
An institution based cross-sectional study was conducted at Debre Markos Referral Hospital in July and August 2016. A total of 234 randomly-selected pregnant women took part in the study. Data on sociodemographic factors, environmental and sanitation factors, reproductive factors, and nutrition related characteristics were collected using a structured questionnaire. Hemoglobin level was determined using hematological analyzer (Cell Dyn 1800) machine. The stool sample was collected to identify intestinal parasitic infections. Statistical analysis was done using logistic regression. The p value of less than 0.05 at 95% confidence interval was considered statistically significant.
RESULTS
The overall prevalence of anemia among pregnant women was 11.5% (95% CI: 8.2%- 14.9%). The result of multivariable analysis revealed that, coffee consumption [AOR = 2.91; 95% CI (1.63, 8.78)], and hookworm infection [AOR = 2.65; 95% CI (1.48, 4.72)] were factors significantly associated with anemia among pregnant women.
CONCLUSION
Anemia is of public health concern among pregnant women in the study area. All pregnant women coming to antenatal clinics should be screened and treated routinely for intestinal parasitic infection. Pregnant women should limit coffee consumption, and avoid drinking coffee with meals.
Topics: Adult; Anemia; Coffee; Ethiopia; Female; Hookworm Infections; Humans; Logistic Models; Pregnancy; Pregnancy Complications, Hematologic; Pregnancy Complications, Parasitic; Pregnant Women; Prenatal Care; Risk Factors; Young Adult
PubMed: 30408080
DOI: 10.1371/journal.pone.0206880 -
CMAJ : Canadian Medical Association... Mar 2013
Topics: Adult; Buttocks; Folliculitis; Hookworm Infections; Humans; Larva Migrans; Male
PubMed: 22872765
DOI: 10.1503/cmaj.120266 -
The American Journal of Tropical... Sep 2013Children (n = 812) 6-11 years of age attending 16 schools in the Kintampo North Municipality of Ghana were screened for participation in a study on hookworm infection,...
Children (n = 812) 6-11 years of age attending 16 schools in the Kintampo North Municipality of Ghana were screened for participation in a study on hookworm infection, nutrition, and response to albendazole. The prevalence of Necator americanus hookworm infection (n = 286) was 39.1%, and significant predictors of infection included age, malaria parasitemia, lack of health care, school area, levels of antibodies against hookworm, and low consumption of animal foods. The cure rate after a single dose (400 mg) albendazole was 43%, and the mean fecal egg count reduction rate was 87.3%. Data for an in vitro egg hatch assay showed a trend toward reduced albendazole susceptibility in post-treatment hookworm isolates (P = 0.06). In summary, hookworm infection is prevalent among school age children in the Kintampo North Municipality and animal food intake inversely correlates with infection status. Modest cure rates and fecal egg count reduction rates reinforce the need for further investigation of potential benzimidazole resistance in Ghana.
Topics: Albendazole; Animals; Antibodies, Helminth; Benzimidazoles; Child; DNA, Helminth; Diet; Feces; Female; Ghana; Hookworm Infections; Humans; Immunoglobulin G; Malaria; Male; Necator americanus; Parasite Egg Count; Plasmodium falciparum; Prevalence; Risk Factors; Socioeconomic Factors; Surveys and Questionnaires
PubMed: 23836564
DOI: 10.4269/ajtmh.12-0605 -
Tropical Medicine & International... May 1999The association between helminth infection and cognitive and motor function was investigated in school-age children in Java, Indonesia. 432 children from 42 primary...
The association between helminth infection and cognitive and motor function was investigated in school-age children in Java, Indonesia. 432 children from 42 primary schools participated in the study. Children were stratified by age and sex into two age groups, 8-9 years and 11-13 years. Children infected with hookworm performed significantly worse than children without hookworm infection in 6 of the 14 cognitive or motor tests. After controlling for school (as a random effect) plus age, socio-economic status and parental education, sex, stunting (height-for-age < - 2sd), body mass index, haemoglobin concentration and the presence of A. lumbricoides and T. trichiura infections, infection with hookworm explained significantly lower scores on tests of Fluency (P < 0.01), Digit-Span Forwards (P < 0.01), Number Choice (P < 0.01), Picture Search (P < 0.03), Stroop Colour Word (P < 0.02) and Mazes (P < 0.001). In 4 of the 6-tests (Fluency, Number Choice, Picture Search and Mazes), there was a significant interaction between hookworm infection and age (P < 0.03), indicating that the association between hookworm and lower test scores increased with age. No associations were observed between hookworm infection and scores in tests of Digit-Span Backwards, Corsi-Block, Stroop Colour, Stroop Interference, Free Recall, Verbal Analogies, Bead Threading or the Pegboard (P > 0.05). Tests associated with helminths represented various functions of working memory. No significant associations between helminth infection and motor function were observed that could not be explained by chance. The results suggest that hookworm infection can have a significant adverse effect on children's working memory which may have consequences for a child's reasoning ability and reading comprehension. Although the results are only associational, the fact that differences in cognition were observed at baseline imply that preventing infection with helminths in school-age children could be of benefit.
Topics: Adolescent; Age Factors; Child; Cognition; Cognition Disorders; Female; Hookworm Infections; Humans; Indonesia; Male; Psychomotor Performance; Regression Analysis
PubMed: 10402967
DOI: 10.1046/j.1365-3156.1999.00410.x -
The Lancet. Microbe Dec 2023Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting... (Randomized Controlled Trial)
Randomized Controlled Trial
Protective efficacy of short-term infection with Necator americanus hookworm larvae in healthy volunteers in the Netherlands: a single-centre, placebo-controlled, randomised, controlled, phase 1 trial.
BACKGROUND
Vaccine development against hookworm is hampered by the absence of the development of protective immunity in populations repeatedly exposed to hookworm, limiting identification of mechanisms of protective immunity and new vaccine targets. Immunisation with attenuated larvae has proven effective in dogs and partial immunity has been achieved using an irradiated larvae model in healthy volunteers. We aimed to investigate the protective efficacy of immunisation with short-term larval infection against hookworm challenge.
METHODS
We did a single-centre, placebo-controlled, randomised, controlled, phase 1 trial at Leiden University Medical Center (Leiden, Netherlands). Healthy volunteers (aged 18-45 years) were recruited using advertisements on social media and in publicly accessible areas. Volunteers were randomly assigned (2:1) to receive three short-term infections with 50 infectious Necator americanus third-stage filariform larvae (50L3) or placebo. Infection was abrogated with a 3-day course of albendazole 400 mg, 2 weeks after each exposure. Subsequently all volunteers were challenged with two doses of 50L3 at a 2-week interval. The primary endpoint was egg load (geometric mean per g faeces) measured weekly between weeks 12 and 16 after first challenge, assessed in the per-protocol population, which included all randomly assigned volunteers with available data on egg counts at week 12-16 after challenge. This study is registered with ClinicalTrials.gov, NCT03702530.
FINDINGS
Between Nov 8 and Dec 14, 2018, 26 volunteers were screened, of whom 23 enrolled in the trial. The first immunisation was conducted on Dec 18, 2018. 23 volunteers were randomly assigned (15 to the intervention group and eight to the placebo group). Egg load after challenge was lower in the intervention group than the placebo group (geometric mean 571 eggs per g [range 372-992] vs 873 eggs per g [268-1484]); however, this difference was not statistically significant (p=0·10). Five volunteers in the intervention group developed a severe skin rash, which was associated with 40% reduction in egg counts after challenge (geometric mean 742 eggs per g [range 268-1484] vs 441 eggs per g [range 380-520] after challenge; p=0·0025) and associated with higher peak IgG1 titres.
INTERPRETATION
To our knowledge, this is the first study to describe a protective effect of short-term exposure to hookworm larvae and show an association with skin response, eosinophilic response, and IgG1. These findings could inform future hookworm vaccine development.
FUNDING
Dioraphte Foundation.
Topics: Humans; Animals; Dogs; Necator americanus; Healthy Volunteers; Netherlands; Hookworm Infections; Immunoglobulin G; Larva
PubMed: 38042152
DOI: 10.1016/S2666-5247(23)00218-5 -
PloS One 2019The eosinophil cationic protein (ECP) is a cytotoxic protein mainly secreted by eosinophils granulocytes and plays a role in host defense against parasitic infections....
BACKGROUND
The eosinophil cationic protein (ECP) is a cytotoxic protein mainly secreted by eosinophils granulocytes and plays a role in host defense against parasitic infections. Infection with Necator americanus (hookworm) is traditionally diagnosed by the Kato-Katz method which is inherently tedious, subjective and known to underestimate infection intensity. This study aimed to assess levels of serum ECP in relation to hookworm infection intensity.
METHODS
Stool samples from 984 (aged 4 to 80 years) participants in a cross-sectional study conducted in the Kintampo North Municipality of Ghana were examined using the Kato-Katz and formol-ether concentration methods. Serum ECP levels were measured by ECP assay kit and compared between 40 individuals infected with hookworm only, 63 with hookworm- Plasmodium falciparum co-infection, 59 with P. falciparum infection and 36 with no infection.
RESULTS
Hookworm infection prevalence was 18.1% (178/984). ECP levels were significantly higher in individuals infected with hookworm only (β = 2.96, 95%CI = 2.69, 3.23, p<0.001) or co-infected with P. falciparum (β = 3.15, 95%CI = 2.91, 3.39, p<0.001) compared to the negative control. Levels of ECP were similar between those with only P. falciparum infection and the uninfected control (p>0.05). Increased hookworm intensity was associated with a significant increase in ECP level (β = 4.45, 95%CI = 2.25, 9.11, rs = 0.193, n = 103, p<0.01). ECP threshold of 84.98ng/ml was associated with a positive predictive value (PPV) of 98% (95% CI = 92, 100), and negative predictive value (NPV) of 76% (95% CI = 62, 87) in classifying hookworm infection status with an AUROC of 96.3%.
CONCLUSION
Serum ECP level may be a good biomarker of hookworm infection and intensity and warrant further investigations to help improve current hookworm diagnosis.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Ancylostomatoidea; Animals; Biomarkers; Child; Child, Preschool; Cross-Sectional Studies; Eosinophil Cationic Protein; Feces; Female; Ghana; Hookworm Infections; Humans; Malaria, Falciparum; Male; Middle Aged; Prevalence
PubMed: 31513658
DOI: 10.1371/journal.pone.0222382 -
Emerging Infectious Diseases Aug 2018During 2012-2015, US-bound refugees living in Myanmar-Thailand border camps (n = 1,839) were surveyed for hookworm infection and treatment response by using quantitative...
During 2012-2015, US-bound refugees living in Myanmar-Thailand border camps (n = 1,839) were surveyed for hookworm infection and treatment response by using quantitative PCR. Samples were collected at 3 time points: after each of 2 treatments with albendazole and after resettlement in the United States. Baseline prevalence of Necator americanus hookworm was 25.4%, Ancylostoma duodenale 0%, and Ancylostoma ceylanicum (a zoonosis) 5.4%. Compared with N. americanus prevalence, A. ceylanicum hookworm prevalence peaked in younger age groups, and blood eosinophil concentrations during A. ceylanicum infection were higher than those for N. americanus infection. Female sex was associated with a lower risk for either hookworm infection. Cure rates after 1 dose of albendazole were greater for A. ceylanicum (93.3%) than N. americanus (65.9%) hookworm (p<0.001). Lower N. americanus hookworm cure rates were unrelated to β-tubulin single-nucleotide polymorphisms at codons 200 or 167. A. ceylanicum hookworm infection might be more common in humans than previously recognized.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Albendazole; Ancylostoma; Ancylostomiasis; Animals; Anthelmintics; Child; Child, Preschool; Feces; Female; Humans; Infant; Male; Middle Aged; Myanmar; Refugees; Thailand; Young Adult
PubMed: 30014834
DOI: 10.3201/eid2408.180280 -
The Korean Journal of Parasitology Aug 2017Hookworm infections are rare causes of acute gastrointestinal bleeding. We report a middle aged man with primary nephrotic syndrome and pulmonary embolism. During the... (Review)
Review
Hookworm infections are rare causes of acute gastrointestinal bleeding. We report a middle aged man with primary nephrotic syndrome and pulmonary embolism. During the treatment with steroids and anticoagulants, the patient presented acute massive hemorrhage of the gastrointestinal tract. The results of gastroscopy showed red worms in the duodenum. Colonoscopy and CT angiogram of abdomen were unremarkable. Capsule endoscopy revealed fresh blood and multiple hookworms in the jejunum and ileum. Hookworms caused the acute intestinal bleeding. The patient responded well to albendazole. Hematochezia was markedly ameliorated after eliminating the parasites. Hence, hookworm infection should be considered in the differential diagnosis of a patient with obscure gastrointestinal bleeding. Capsule endoscopy may offer a better means of diagnosis for intestinal hookworm infections.
Topics: Acute Disease; Albendazole; Ancylostomatoidea; Animals; Anthelmintics; Capsule Endoscopy; Diagnosis, Differential; Duodenum; Endoscopy, Gastrointestinal; Gastrointestinal Hemorrhage; Hookworm Infections; Humans; Ileum; Jejunum; Male; Middle Aged; Treatment Outcome
PubMed: 28877573
DOI: 10.3347/kjp.2017.55.4.417