1
|
Holland CV. The long and winding road of Ascaris larval migration: the role of mouse models. Parasitology 2021; 148:1-9. [PMID: 33612124 PMCID: PMC8660642 DOI: 10.1017/s0031182021000366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/14/2021] [Accepted: 02/16/2021] [Indexed: 11/27/2022]
Abstract
Ascaris lumbricoides and Ascaris suum are helminth parasites of humans and pigs, respectively. The life cycle of Ascaris sets it apart from the other soil-transmitted helminths because of its hepato-tracheal migration. Larval migration contributes to underestimated morbidity in humans and pigs. This migration, coupled with a lack of a murine model in which the Ascaris parasite might complete its life cycle, has undoubtedly contributed to the neglected status of the ascarid. Our knowledge of the epidemiology of adult worm infections had led us to an enhanced understanding of patterns of infection such as aggregation and predisposition; however, the mechanisms underlying these complex phenomena remain elusive. Carefully controlled experiments in defined inbred strains of mice – with enhanced recovery of larvae in tandem with measurements of cellular, histopathological and molecular processes – have greatly enhanced our knowledge of the early phase of infection, a phase crucial to the success or failure of adult worm establishment. Furthermore, the recent development of a mouse model of susceptibility and resistance, with highly consistent and diverging Ascaris larval burdens in the murine lungs, represents the extremes of the host phenotype displayed in the aggregated distribution of worms and provides an opportunity to explore the mechanistic basis that confers predisposition to light and heavy Ascaris infection. Certainly, detailed knowledge of the cellular hepatic and pulmonary responses at the molecular level can be accrued from murine models of infection and, once available, may enhance our ability to develop immunomodulatory therapies to elicit resistance to infection.
Collapse
Affiliation(s)
- C. V. Holland
- Department of Zoology, School of Natural Sciences, Trinity College, Dublin 2, Ireland
| |
Collapse
|
2
|
|
3
|
Zanwar VG, Pawar SV, Jain SS, Rathi SP, Contractor QQ, Rathi PM. An unusual cause of overt gastrointestinal bleeding in a malnourished child. Trop Doct 2015; 46:100-2. [PMID: 26264463 DOI: 10.1177/0049475515598667] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Trichuris trichiura (T. Trichiura) is a known parasite infestation among tropical children. Humans acquire Trichuriasis infection after ingestion of embryonated eggs via contaminated food or water. Most of them are asymptomatic. A severe form of trichuris infestation is known as Trichuris dysentery syndrome (TDS). It manifests as mucous diarrhoea, bleeding, malnutrition and stunting, or even life-threatening anaemia. We are reporting an interesting case of a 7-year-old girl who presented with bloody diarrhoea for 2 years. Her growth was stunted as she was not gaining weight. Severe inflammatory bowel disease was suspected clinically. Physical examination revealed marked pallor, pedal oedema and koilonychia along with sparse and hypopigmented hair. On evaluationT. Trichiurahelminths were seen on stool examination and massive worm load was visualised directly on colonoscopy. A diagnosis of TDS was made. She was successfully treated with oral Albendazole (400 mg) and blood transfusion.
Collapse
Affiliation(s)
- Vinay G Zanwar
- Topiwala National Medical College and BYL Nair Charitable Hospital Mumbai, Maharashtra, India
| | - Sunil V Pawar
- Topiwala National Medical College and BYL Nair Charitable Hospital Mumbai, Maharashtra, India
| | - Samit S Jain
- Topiwala National Medical College and BYL Nair Charitable Hospital Mumbai, Maharashtra, India
| | - Surabhi P Rathi
- Topiwala National Medical College and BYL Nair Charitable Hospital Mumbai, Maharashtra, India
| | - Qais Q Contractor
- Topiwala National Medical College and BYL Nair Charitable Hospital Mumbai, Maharashtra, India
| | - Pravin M Rathi
- Topiwala National Medical College and BYL Nair Charitable Hospital Mumbai, Maharashtra, India
| |
Collapse
|
4
|
Bianucci R, Torres EJL, Santiago JMFD, Ferreira LF, Nerlich AG, Souza SMMD, Giuffra V, Chieffi PP, Bastos OM, Travassos R, Souza WD, Araújo A. Trichuris trichiura in a post-Colonial Brazilian mummy. Mem Inst Oswaldo Cruz 2015; 110:145-7. [PMID: 25742276 PMCID: PMC4371230 DOI: 10.1590/0074-02760140367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/16/2014] [Indexed: 11/23/2022] Open
Abstract
Trichuris trichiura is a soil-transmitted helminth which is prevalent in warm, moist,
tropical and subtropical regions of the world with poor sanitation. Heavy whipworm
can result either in Trichuris dysenteric syndrome - especially in children - or in a
chronic colitis. In heavy infections, worms can spread proximally and may cause
ileitis. Here we provide first microscopic evidence for a T. trichiura adult worm
embedded in the rectum of a post-Colonial Brazilian adult mummy. During Colonial and
post-Colonial times, many European chroniclers described a parasitic disease named
Maculo whose symptomatology coincides with heavy helminthiasis. Based on our findings
and on comparison of ancient textual evidence with modern description of heavy
whipworm, we feel confident in considering that the two syndromes are expressions of
the same pathological condition.
Collapse
Affiliation(s)
- Rafaella Bianucci
- Department of Public Health and Paediatric Sciences, University of Turin, Turin, Italy
| | - Eduardo J Lopes Torres
- Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | | | - Luis F Ferreira
- Escola Nacional de Saúde Pública Sérgio Arouca, Fiocruz, Rio de Janeiro, RJ, Brasil
| | | | | | | | - Pedro Paulo Chieffi
- Departamento de Patologia, Faculdade de Ciências Médicas, Santa Casa de São Paulo, São Paulo, SP, Brasil
| | - Otilio Maria Bastos
- Departamento de Microbiologia e Parasitologia, Centro de Ciências da Saúde, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - Renata Travassos
- Instituto de Biofísica Carlos Chagas Filho, Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - Adauto Araújo
- Escola Nacional de Saúde Pública Sérgio Arouca, Fiocruz, Rio de Janeiro, RJ, Brasil
| |
Collapse
|
5
|
Genome and transcriptome of the porcine whipworm Trichuris suis. Nat Genet 2014; 46:701-6. [PMID: 24929829 PMCID: PMC4105696 DOI: 10.1038/ng.3012] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 05/22/2014] [Indexed: 12/15/2022]
Abstract
Trichuris (whipworm) infects 1 billion people worldwide and causes a disease (trichuriasis) that results in major socioeconomic losses in both humans and pigs. Trichuriasis relates to an inflammation of the large intestine manifested in bloody diarrhea, and chronic disease can cause malnourishment and stunting in children. Paradoxically, Trichuris of pigs has shown substantial promise as a treatment for human autoimmune disorders, including inflammatory bowel disease (IBD) and multiple sclerosis. Here we report whole-genome sequencing at ∼140-fold coverage of adult male and female T. suis and ∼80-Mb draft assemblies. We explore stage-, sex- and tissue-specific transcription of mRNAs and small noncoding RNAs.
Collapse
|
6
|
Helmby H. Immunity to gastrointestinal nematodes: a story of immune modulation. Expert Rev Clin Immunol 2014; 1:475-82. [DOI: 10.1586/1744666x.1.3.475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
7
|
Soga K, Yamada M, Naito Y, Yoshikawa T, Arizono N. Mucin-Related Molecular Responses of Bronchial Epithelial Cells in Rats Infected with the Nematode Nippostrongylus brasiliensis. ISRN PARASITOLOGY 2013; 2013:804585. [PMID: 27335862 PMCID: PMC4890922 DOI: 10.5402/2013/804585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Accepted: 02/18/2013] [Indexed: 11/23/2022]
Abstract
Although mucins are essential for the protection of internal epithelial surfaces, molecular responses involving mucin production and secretion in response to various infectious agents in the airway have not been fully elucidated. The present study analysed airway goblet cell mucins in rats infected with the nematode Nippostrongylus brasiliensis, which migrates to the lungs shortly after infection. Goblet cell hyperplasia occurred in the bronchial epithelium 3-10 days after infection. The high iron diamine-alcian blue staining combined with neuraminidase treatment showed that sialomucin is the major mucin in hyperplastic goblet cells. Immunohistochemical studies demonstrated that goblet cell mucins were immunoreactive with both the major airway mucin core peptide, Muc5AC, and the major intestinal mucin core peptide Muc2. Reverse transcription real-time PCR studies demonstrated upregulation of gene transcription levels of Muc5AC, Muc2, the sialyltransferase St3gal4, and the resistin-like molecule beta (Retnlb) in the lungs. These results showed that nematode infection induces airway epithelial responses characterised by the production of sialomucin with Muc5AC and Muc2 core peptides. These mucins, as well as Retnlb, might have important roles in the protection of mucosa from migrating nematodes in the airway.
Collapse
Affiliation(s)
- Koichi Soga
- Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602-8566, Japan; Department of Medical Zoology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Minoru Yamada
- Department of Medical Zoology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Yuji Naito
- Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602-8566, Japan
| | - Toshikazu Yoshikawa
- Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kyoto 602-8566, Japan
| | - Naoki Arizono
- Department of Medical Zoology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| |
Collapse
|
8
|
Cantacessi C, Young ND, Nejsum P, Jex AR, Campbell BE, Hall RS, Thamsborg SM, Scheerlinck JP, Gasser RB. The transcriptome of Trichuris suis--first molecular insights into a parasite with curative properties for key immune diseases of humans. PLoS One 2011; 6:e23590. [PMID: 21887281 PMCID: PMC3160910 DOI: 10.1371/journal.pone.0023590] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 07/20/2011] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Iatrogenic infection of humans with Trichuris suis (a parasitic nematode of swine) is being evaluated or promoted as a biological, curative treatment of immune diseases, such as inflammatory bowel disease (IBD) and ulcerative colitis, in humans. Although it is understood that short-term T. suis infection in people with such diseases usually induces a modified Th2-immune response, nothing is known about the molecules in the parasite that induce this response. METHODOLOGY/PRINCIPAL FINDINGS As a first step toward filling the gaps in our knowledge of the molecular biology of T. suis, we characterised the transcriptome of the adult stage of this nematode employing next-generation sequencing and bioinformatic techniques. A total of ∼65,000,000 reads were generated and assembled into ∼20,000 contiguous sequences ( = contigs); ∼17,000 peptides were predicted and classified based on homology searches, protein motifs and gene ontology and biological pathway mapping. CONCLUSIONS These analyses provided interesting insights into a number of molecular groups, particularly predicted excreted/secreted molecules (n = 1,288), likely to be involved in the parasite-host interactions, and also various molecules (n = 120) linked to chemokine, T-cell receptor and TGF-β signalling as well as leukocyte transendothelial migration and natural killer cell-mediated cytotoxicity, which are likely to be immuno-regulatory or -modulatory in the infected host. This information provides a conceptual framework within which to test the immunobiological basis for the curative effect of T. suis infection in humans against some immune diseases. Importantly, the T. suis transcriptome characterised herein provides a curated resource for detailed studies of the immuno-molecular biology of this parasite, and will underpin future genomic and proteomic explorations.
Collapse
Affiliation(s)
- Cinzia Cantacessi
- Department of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Neil D. Young
- Department of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Peter Nejsum
- Departments of Veterinary Disease Biology and Basic Animal and Veterinary Science, University of Copenhagen, Frederiksberg, Denmark
| | - Aaron R. Jex
- Department of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Bronwyn E. Campbell
- Department of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Ross S. Hall
- Department of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Stig M. Thamsborg
- Departments of Veterinary Disease Biology and Basic Animal and Veterinary Science, University of Copenhagen, Frederiksberg, Denmark
| | - Jean-Pierre Scheerlinck
- Department of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
- Centre for Animal Biotechnology, The University of Melbourne, Parkville, Australia
| | - Robin B. Gasser
- Department of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
9
|
Abstract
Ascaris lumbricoides and Ascaris suum are widespread parasitic nematodes of humans and pigs respectively. Recent prevalence data suggests that approximately 1.2 billion people are infected. Adult worms exhibit an overdispersed frequency distribution in their hosts and individuals harbouring heavy burdens display associated morbidity. In this review, we describe the parasite, its distribution and measures undertaken to control infection.
Collapse
Affiliation(s)
- Christina Dold
- Department of Zoology, School of Natural Science, Trinity College, Dublin 2, Ireland.
| | | |
Collapse
|
10
|
Lauwers G, Mino-Kenudson M, Kradin RL. Infections of the Gastrointestinal Tract. DIAGNOSTIC PATHOLOGY OF INFECTIOUS DISEASE 2010. [PMCID: PMC7152102 DOI: 10.1016/b978-1-4160-3429-2.00009-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
11
|
Abstract
AbstractAscaris lumbricoides and Ascaris suum are important helminth parasites of humans and pigs, respectively. Although it is now well established that the presence of mature adult worms in the host intestine contributes to significant nutritional morbidity, the impact of larval migratory ascariasis is far less well understood. The development of a mouse model to explore susceptibility and resistance to larval ascariasis in the lungs provided an opportunity to observe the impact of larval migration on host growth during the course of infection. Changes in body weight were monitored in two strains of inbred mice, the susceptible C57BL/6j and the resistant CBA/Ca. Groups of mice received one of four doses: 100, 500, 1000 and 3000 fully embryonated A. suum ova. Infected mice underwent post-mortem on days 6, 7 and 8 post-infection. Control mice received a placebo dose of intubation medium and underwent post-mortem on day 7 post-infection. Mice were weighed pre-infection (day 0) and post-infection on the day of post-mortem. At post-mortem, the lungs of each mouse were removed for enumeration of Ascaris larval burdens by means of the modified Baermann method. Control mice of each strain showed an increase in weight from pre-infection to post-infection day. Within the C57BL/6j strain, mice infected with higher doses of Ascaris eggs experienced a reduction in body weight; for those given 3000 eggs this was on all three post-mortem days, and for those given 1000, on days 7 and 8. For CBA/Ca mice, only mice receiving the 3000 dose demonstrated a reduction in body weight. These findings suggest that larval migratory ascariasis has a significant negative impact upon host growth and that this is related to infective dose and larval burden.
Collapse
|
12
|
|
13
|
Mukhopadhyay C, Wilson G, Chawla K, VS B, Shivananda PG. A 6 year Geohelminth infection profile of children at high altitude in Western Nepal. BMC Public Health 2008; 8:98. [PMID: 18366807 PMCID: PMC2335097 DOI: 10.1186/1471-2458-8-98] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 03/27/2008] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Geohelminth infections are a major problem of children from the developing countries. Children with these infections suffer from developmental impairments and other serious illnesses. This study aimed to measure the prevalence of geohelminth infection, infection intensity as well as the change in the intensity in children from Western Nepal over years. METHODS This 6-year hospital based prospective study at the Manipal Teaching Hospital, Pokhara included children (< 15 years) visiting the hospital from Kaski and 7 surrounding districts. Samples were also collected from children in the community from different medical camps. Three stool samples from every child were processed using direct and concentration methods. The Kato-Katz technique was used for measuring the intensity of infection. RESULTS The overall prevalence in hospital - attending children was 9.2% with 7.6% in preschool (0 - 5 y) and 11.0% in school-age (6 - 15 y) children, and in community 17.7% with 14.8% in pre-school and 20.5% in school-age children. Ascaris lumbricoides, Trichuris trichiura, Ancylostoma deodenale and Strongyloides stercoralis were the common geohelminths with a gradual decrease in worm load over the years. School-age children were found to be significantly more prone to geohelminth infection as compared to preschool children, but no statistical difference was detected by gender, district as well as season. CONCLUSION This heavy infection of geohelminths in children should be corrected by appropriate medication and maintaining strict personal hygiene. Health education, clean water, good sewage management and a congenial environment should be ensured to minimise infection.
Collapse
Affiliation(s)
- Chiranjay Mukhopadhyay
- Department of Microbiology, Kasturba Medical College, Manipal University, Karnataka, India
| | - Godwin Wilson
- Laboratory medicine and pathology, Al-Khor Hospital, Hamad Medical Corporation, Doha, Qatar
| | - Kiran Chawla
- Department of Microbiology, Kasturba Medical College, Manipal University, Karnataka, India
| | - Binu VS
- Department of Statistics, Manipal University, Karnataka, India
| | - PG Shivananda
- Department of Microbiology, Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, India
| |
Collapse
|
14
|
Alkazmi LMM, Dehlawi MS, Behnke JM. The effect of the hookworm Ancylostoma ceylanicum on the mucosal architecture of the small intestine in hamsters. J Helminthol 2007; 80:397-407. [PMID: 17125550 DOI: 10.1017/joh2006372] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
AbstractHookworms are known to cause marked changes to the intestinal mucosa, especially in relation to erosion of the villi. However, since the development of enteropathy has not been examined thoroughly through quantitative experiments on infected animals, the results of experiments conducted in hamsters infected with Ancylostoma ceylanicum are reported. Changes to intestinal architecture were first apparent between 12 and 14 days after infection, and then increased in intensity for 3–4 weeks, persisting for as long as worms were present (>63 days). Following infection, the height of villi declined from a mean of 1002 μm in naïve controls to less than 200 μm and as low as 18 μm in one case. The depth of the crypts of Lieberkuhn increased from a baseline value of 166 μm in naïve controls to in excess of 600 μm within 6 weeks of infection. Mitotic figures had a baseline value of 5.5 per villus-crypt unit, and this rose to in excess of 25 in some experiments. Changes were dependent on the intensity of the parasite burden on day 20, but by 30 days after infection changes in all three values were maximal and density-dependent relationships were no longer clearly apparent. Villus height and crypt depth returned to near normal values within a week of the removal of worms, although group means for both remained different from naïve controls for at least 3 weeks after treatment. Cellular division, as reflected in numbers of mitotic figures, stayed elevated for over 5 weeks after removal of worms. The results suggest that enteropathy in hookworm infections stems from a combination of intestinal immune responses and from the grazing activities of the adult worms on the mucosal surface, but is not sufficient per se for expulsion of this parasite.
Collapse
Affiliation(s)
- L M M Alkazmi
- School of Biology, University of Nottingham, University Park, Nottingham, UK
| | | | | |
Collapse
|
15
|
Grigorenko EL, Sternberg RJ, Jukes M, Alcock K, Lambo J, Ngorosho D, Nokes C, Bundy DA. Effects of antiparasitic treatment on dynamically and statically tested cognitive skills over time. JOURNAL OF APPLIED DEVELOPMENTAL PSYCHOLOGY 2006. [DOI: 10.1016/j.appdev.2006.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
16
|
Fujiwara RT, Geiger SM, Bethony J, Mendez S. Comparative immunology of human and animal models of hookworm infection. Parasite Immunol 2006; 28:285-93. [PMID: 16842265 DOI: 10.1111/j.1365-3024.2006.00821.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hookworm infection is a major cause of disease burden for animals and humans. Over the past years, the use of animal models in hookworm infections has been driven by the search of new anthelminthic therapies and, especially, vaccine development. These studies also contributed to the advance of knowledge on immunity to hookworms, offering new insights to understand the nature of this parasitic infection. In this article, we will summarize the essential features of the immune response in the two major animal models of hookworm infections (dog and hamster) and then consider its implication for the human immune response.
Collapse
Affiliation(s)
- R T Fujiwara
- Department of Microbiology, Immunology and Tropical Medicine, The George Washington University, Washington, DC, USA.
| | | | | | | |
Collapse
|
17
|
Mendez S, Valenzuela JG, Wu W, Hotez PJ. Host cytokine production, lymphoproliferation, and antibody responses during the course of Ancylostoma ceylanicum infection in the Golden Syrian hamster. Infect Immun 2005; 73:3402-7. [PMID: 15908367 PMCID: PMC1111885 DOI: 10.1128/iai.73.6.3402-3407.2005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Syrian Golden hamster (Mesocricetus auratus) has been used to model infections with the hookworm Ancylostoma ceylanicum. New molecular immunological reagents to measure cellular immune responses in hamsters were developed and used to determine the impact of A. ceylanicum hookworm infection on host cytokine responses and lymphoproliferation. Initial larval infection with 100 third-stage A. ceylanicum larvae resulted in predominant Th1 responses (upregulation of proinflammatory cytokines) that lasted for the duration of larval migration and continued up to 14 days postinfection (prepatency). Subsequently, development of larvae into egg-laying adult hookworms (patency) coincided with a switch to Th2 predominant responses (interleukin-4 [IL-4]) as well as a marked increase in IL-10 production. This switch also concurred with reduced host lymphoproliferative responses to hookworm antigens. The findings demonstrate a similarity in immune responses between hamsters and humans infected with hookworms, suggesting that hamsters will be a useful animal model species for examining host immunity to human hookworm infections.
Collapse
Affiliation(s)
- Susana Mendez
- Department of Microbiology and Tropical Medicine, The George Washington University Medical Center, Ross Hall, Rm 726, 2300 Eye St. NW, Washington, DC 20037, USA.
| | | | | | | |
Collapse
|
18
|
Abstract
Immune responses to human roundworm (Ascaris lumbricoides) and whipworm (Trichuris trichiura) and their role in controlling worm populations are reviewed. Recent immunoepidemiological data implicate T(H)2-mediated responses in limiting A. lumbricoides and T. trichiura populations. Reinfection studies further suggest that IL-5 cytokine responses are negatively associated with adult recruitment in T. trichiura but not A. lumbricoides and may therefore be involved in negative intraspecific and interspecific interactions mediated through the host immune system. The importance of inducible immunoregulatory networks in the ecology of the host-parasite relationship is considered, with particular regard to possible manipulative strategies by the parasites. This aspect of the worms' interaction with the host immune system is both poorly known and potentially central to an understanding of parasite population dynamics and the evolutionary pressures that have shaped present-day host-parasite associations. Some possible implications of worm-mediated immunomodulation for the occurrence of bystander infectious diseases in human populations and the management of de-worming programmes are also discussed.
Collapse
Affiliation(s)
- J E Bradley
- School of Biology, Nottingham University, Nottingham NG7 2RD, UK.
| | | |
Collapse
|
19
|
Abstract
Gastrointestinal nematode infection is extremely prevalent worldwide in humans and animals. Infection levels vary between individuals in infected populations and exhibit a negative binomial distribution, and some individuals appear to be predisposed to certain infection levels. Moreover, infection tends to be chronic, despite evidence for the acquisition of some degree of acquired immunity. The host is subject to constant and repeated antigenic challenge, and individuals vary in the response they make. While a considerable amount of information is emerging on the immunoregulatory mechanisms operating during acute nematode infection from a variety of laboratory model systems, relatively little work has been carried out on the immune mechanisms underlying chronic infection. This review details some of the work that has addressed this important facet of gut nematode infection, highlighting studies from model systems that give insight into the induction of nonprotective immunity, while at the same time avoiding the induction of host-damaging pathology.
Collapse
Affiliation(s)
- Kelly S Hayes
- School of Biological Sciences, University of Manchester, UK
| | | | | |
Collapse
|
20
|
Geiger SM, Massara CL, Bethony J, Soboslay PT, Corrêa-Oliveira R. Cellular responses and cytokine production in post-treatment hookworm patients from an endemic area in Brazil. Clin Exp Immunol 2004; 136:334-40. [PMID: 15086399 PMCID: PMC1809034 DOI: 10.1111/j.1365-2249.2004.02449.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Human hookworm infections are distributed widely in tropical areas and have a significant impact on host morbidity and human health. In the present study, we investigated the cellular responsiveness and cytokine production in peripheral blood mononuclear cells (PBMC) from Necator americanus-infected schoolchildren who had recently received chemotherapy, and compared them with non-infected endemic controls. Hookworm patients and treated, egg-negative individuals showed a lower cellular reactivity against phytohaemagglutinin (PHA) and hookworm antigen when compared with egg-negative endemic controls. The baseline production of proinflammatory tumour necrosis factor-alpha (TNF-alpha) in PBMC from infected patients and treated, egg-negative individuals was elevated. On the other hand, PHA- or hookworm antigen-induced interleukin (IL)-12 and interferon (IFN)-gamma secretion was higher in endemic controls than in hookworm patients, who either continued egg-positive or were egg-negative after treatment. Also, PBMC from endemic controls secreted more IL-5 and IL-13 than the other patient groups. Opposite to that, the spontaneous as well as the antigen-driven IL-10 secretion was lower in endemic controls when compared with the other groups. In summary, patently hookworm-infected as well as egg-negative treated patients disclosed an elevated spontaneous cellular secretion of proinflammatory TNF-alpha, a prominent secretion of regulatory Th2-type IL-10 and an impaired production of IL-12, IFN-gamma, IL-5 and IL-13.
Collapse
Affiliation(s)
- S M Geiger
- Fundação Oswaldo Cruz, Centro de Pesquisas René Rachou, Laboratório de Imunologia, Belo Horizonte-MG, Brazil.
| | | | | | | | | |
Collapse
|
21
|
Abstract
Parasitic gastrointestinal (GI) nematodes are one of the most commonly acquired infections in the world. Although they cause relatively little mortality, infections result in high levels of morbidity that can result in developmental consequences in infected children and cause significant economic loss in infected animals. Over the last 30 years there has been extensive research into the mechanisms controlling the expulsion of gastrointestinal nematodes. Although many of the effector mechanisms that contribute to the loss of the parasite have been defined, we still appear to be some way from understanding the actual cause of parasite loss. Part of this stems from the different responses induced by different gastrointestinal parasites. It is clear that a Th2 response is essential for the expulsion of GI helminths; however, each of the characteristic immunological effector mechanisms induced following infection with these parasites may not be required or may be insufficient in isolation, but together they operate to expel GI helminths. These responses then succeed more efficiently in some cases than in others to induce parasite expulsion. The contribution made by various effector mechanisms to the expulsion of these parasites may therefore be a reflection of both the niche which the parasite inhabits as well as possible evasive/suppressive mechanisms employed by the parasites. In this review the various aspects of parasite expulsion will be described and the controversial issues in the field will be discussed.
Collapse
|
22
|
Nishiura H, Imai H, Nakao H, Tsukino H, Changazi MA, Hussain GA, Kuroda Y, Katoh T. Ascaris lumbricoides among children in rural communities in the Northern Area, Pakistan: prevalence, intensity, and associated socio-cultural and behavioral risk factors. Acta Trop 2002; 83:223-31. [PMID: 12204395 DOI: 10.1016/s0001-706x(02)00116-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The prevalence and intensity of Ascaris lumbricoides in 492 children from five rural villages in the Northern Area of Pakistan was examined. The overall prevalence of A. lumbricoides was 91% (95%CI 88.6-93.6) with geometric mean (GM) egg count intensities of 3985 eggs per g (epg). The most intense A. lumbricoides infections were found in children aged 5-8 years. We also investigated selected socio-cultural and behavioral variables for A. lumbricoides infections that might be relevant for the design of appropriate prevention and control programs. Univariate analysis associated A. lumbricoides intensity with age (P=0.004), location of household (P<0.01), defecation practices (P=0.02), soil eating habit (P<0.01), hand washing after defecation (P<0.01), and living with children under 5 years old (P=0.02). Multivariate analysis identified the children's age 5-8 (P<0.01), location of household in Surngo, Askole, and Stakchun where the pilot health care model activities were not done (P<0.01), and living with children under 5 years old (P=0.03) as variables statistically associated with the intensity of A. lumbricoides. The results indicated that there were certain clear risk factors in A. lumbricoides transmission, and that its intensity was influenced by age-related behavioral and environmental factors that contribute to exposure.
Collapse
Affiliation(s)
- Hiroshi Nishiura
- Department of Public Health, School of Medicine, Miyazaki Medical College, 5200 Kihara, Kiyotake, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Muniz-Junqueira MI, Queiroz EFO. Relationship between protein-energy malnutrition, vitamin A, and parasitoses in living in Brasília. Rev Soc Bras Med Trop 2002; 35:133-41. [PMID: 12011921 DOI: 10.1590/s0037-86822002000200002] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is still controversial whether intestinal parasitic infections can influence the nutritional status of children. The relationship between protein-energy malnutrition, vitamin A and parasitic infections was evaluated in 124 children. The food intake estimated by recall method was generally low and poor. Seventy five percent of the children were infected with intestinal parasites. The mean+/-SD weight-for-age and height-for-age Z-score were skewed one standard deviation to the left, when compared to normal standards. An association was found between protein-energy malnutrition and Giardia lamblia, but not with Ascaris lumbricoides or Hymenolepis nana infection. Only Giardia-infected children had a decreased weight-for-age and weight-for-height Z-score. Hypovitaminosis A was a major nutritional problem, but no relationship between this deficiency and parasitic infection was found. Our data indicate that low and poor food intake were the major cause of protein-energy malnutrition among the children, and except for Giardia, this was not influenced by parasitic infections.
Collapse
Affiliation(s)
- Maria Imaculada Muniz-Junqueira
- Laboratório de Imunologia Celular, Area de Patologia, Faculdade de Medicina, Universidade de Brasília, Brasília, DF, Brasil.
| | | |
Collapse
|
24
|
Abstract
Trichuris trichiura is a highly prevalent intestinal helminth of humans with a well-characterized animal model, Trichuris muris in the mouse. Relating the murine work back to the human infection has been difficult, however, as many of the questions addressed in the mouse cannot be asked in humans. The ability to reconstitute a mouse with a human immune system could help bridge this gap, allowing a human immune response to be studied under a controllable laboratory environment. In this study, we demonstrate that severe combined immunodeficient mice engrafted with naïve human peripheral blood lymphocytes are capable of mounting a Trichuris specific human antibody response after vaccination with T. muris antigens. The phenotype of the response depended on the vaccinating antigen with excretory/secretory antigens eliciting a human immunoglobulin IgG2 response, and whole worm homogenate stimulating IgG1 and IgG2 responses. Vaccination with homogenate also enhanced a human IgG response against a 66-kDa component of T. muris homogenate in a donor-dependent manner. This work shows the potential of using the humanized mouse model for studying the immune responses of humans living in T. trichiura endemic areas.
Collapse
Affiliation(s)
- Matthew D Taylor
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh and School of Biological Sciences, University of Manchester, Manchester, UK.
| | | |
Collapse
|
25
|
Gilgen DD, Mascie-Taylor CG, Rosetta LL. Intestinal helminth infections, anaemia and labour productivity of female tea pluckers in Bangladesh. Trop Med Int Health 2001; 6:449-57. [PMID: 11422959 DOI: 10.1046/j.1365-3156.2001.00729.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We conducted a randomized clinical intervention trial over 24 weeks on a tea estate in north-east Bangladesh to investigate the effect of iron supplementation and anthelmintic treatment on the labour productivity of adult female tea pluckers. A total of 553 full-time tea pluckers, not pregnant and not breastfeeding, were randomly assigned to one of the four intervention groups: group 1 received iron supplementation on a weekly basis, group 2 received anthelmintic treatment at the beginning and half-way through the trial (week 12), group 3 received both iron supplementation as group 1 and anthelmintic treatment as group 2, and group 4 was a control group and received placebos. No significant difference in labour productivity was found between the four intervention groups over the trial period. However, there was a negative association for all three worms (Ascaris lumbricoides, Trichuris trichiura and hookworms) between the intensity of helminth infections (eggs/g faeces) and all measures of labour productivity. Lower haemoglobin values and anaemia (< 120 g/l Hb) were both associated with lower labour productivity and more days sick and absent. Taller women with greater arm circumference were able to pluck more green leaves, earn higher wages and were absent less often.
Collapse
Affiliation(s)
- D D Gilgen
- Department of Biological Anthropology, University of Cambridge, UK.
| | | | | |
Collapse
|
26
|
Flores A, Esteban JG, Angles R, Mas-Coma S. Soil-transmitted helminth infections at very high altitude in Bolivia. Trans R Soc Trop Med Hyg 2001; 95:272-7. [PMID: 11490995 DOI: 10.1016/s0035-9203(01)90232-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
A cross-sectional study of soil-transmitted helminthiases in the Northern Bolivian Altiplano was carried out over the 6-year period 1992-97. Prevalences, intensities and associations were analysed from coprological results obtained in 31 surveys (28 in schools and 3 in individuals of all age-groups) performed in 24 Aymara communities located between the city of La Paz and Lake Titicaca, at an altitude of 3800-4200 m. Ascaris lumbricoides and Trichuris trichiura were detected, with local prevalences in the range 1.2-28.0% and 0.0-24.0%, respectively. Significant differences in prevalence rates of trichuriasis were detected, with highest prevalences in male schoolchildren and in subjects aged > 40 years. The global intensity ranged from 24 to 86,544 eggs per gram of faeces (epg) and from 24 to 4560 epg for ascariasis and trichuriasis, respectively. Higher intensities were noted in girls. A. lumbricoides egg counts were statistically significantly higher in the 5-8-years age-group. A positive association between A. lumbricoides and T. trichiura infections was detected. The proportion of heavy infections for A. lumbricoides was 0.1% and 1.0% in the school and community surveys, respectively. No heavy infection for T. trichiura was detected. The very high altitude and its severe environmental conditions may determine the relatively low prevalences and intensities in this area.
Collapse
Affiliation(s)
- A Flores
- Departamento de Parasitología, Facultad de Farmacia, Universidad de Valencia, Av. Vicente Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain
| | | | | | | |
Collapse
|
27
|
Smith H, Dekaminsky R, Niwas S, Soto R, Jolly P. Prevalence and intensity of infections of Ascaris lumbricoides and Trichuris trichiura and associated socio-demographic variables in four rural Honduran communities. Mem Inst Oswaldo Cruz 2001; 96:303-14. [PMID: 11313635 DOI: 10.1590/s0074-02762001000300004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Between January and March 1998, a cross-sectional survey was carried out in four rural communities in Honduras, Central America. We examined the prevalence and intensity of Ascaris lumbricoides and Trichuris trichiura infections among 240 fecal specimens, and the association between selected socio-demographic variables and infection for 62 households. The overall prevalence of A. lumbricoides and T. trichiura was 45% (95% CI 39.0-51.9) and 38% (95% CI 31.8-44.4) respectively. The most intense infections for Ascaris and Trichuris were found in children aged 2-12 years old. By univariate analysis variables associated with infections of A. lumbricoides were: number of children 2-5 years old (p=0.001), level of formal education of respondents (p=0.01), reported site of defecation of children in households (p=0.02), households with children who had a recent history of diarrhea (p=0.002), and the location of households (p=0.03). Variables associated with both A. lumbricoides and T. trichiura infection included: number of children 6-14 years old (p=0.01, p=0.04, respectively), ownership of a latrine (p=0.04, p=0.03, respectively) and coinfection with either helminth (p=0.001, p=0.001, respectively). By multivariate analysis the number of children 2-5 years living in the household, (p=0.01, odds ratio (OR)=22.2), children with a recent history of diarrhea (p=0.0, OR=39.8), and infection of household members with T. trichiura (p=0.02, OR=16.0) were associated with A. lumbricoides infection. The number of children 6-14 years old in the household was associated with both A. lumbricoides and T. trichiura infection (p=0.04, p=0.01, OR=19.2, OR=5.2, respectively).
Collapse
Affiliation(s)
- H Smith
- Department of Epidemiology and International Health, School of Public Health, University of Alabama, Birmingham, Alabama, USA
| | | | | | | | | |
Collapse
|
28
|
Barreto ML, Strina A, Faria JA, Nobre AA, Jesus SR. [Prevalence and intensity of infection by intestinal parasites in school-aged children in the City of Salvador (Bahia, Brazil)]. Rev Soc Bras Med Trop 2001; 34:99-101. [PMID: 11340505 DOI: 10.1590/s0037-86822001000100016] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
As part of a major study to evaluate the relationship between environmental changes and occurrence of the infection, prevalence and intensity of infection by intestinal parasites was studied in a sample of school children aged 7 to 14 years living in the City of Salvador. The prevalence of infection by at least one species of protozoa or helminth was 66.1%. Prevalence of infection by helminths increased with age. For all helminth species male children presented the highest prevalence.
Collapse
|
29
|
Northrop-Clewes CA, Rousham EK, Mascie-Taylor CN, Lunn PG. Anthelmintic treatment of rural Bangladeshi children: effect on host physiology, growth, and biochemical status. Am J Clin Nutr 2001; 73:53-60. [PMID: 11124750 DOI: 10.1093/ajcn/73.1.53] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The effect of helminth infestation on the nutrition, growth, and physiology of the host is still poorly understood. Anthelmintic treatment of children in developing countries has had varying success in terms of growth improvements. OBJECTIVE The objective of this study was to assess the effect of regular deworming on child growth, physiology, and biochemical status. DESIGN The study was a 12-mo longitudinal intervention in 123 Bangladeshi children aged 2-5 y. Treatment (mebendazole) or placebo tablets were administered every 2 mo for 8 mo and again at 12 mo. Weight, height, midupper arm circumference, intestinal permeability, plasma albumin, alpha(1)-antichymotrypsin, and total protein concentration were assessed every 2 mo. RESULTS Treatment with mebendazole reduced the prevalence of Ascaris lumbricoides from 78% to 8%, of Trichuris trichiura from 65% to 9%, and of hookworm from 4% to 0%. There was no significant difference in the growth of treated children compared with those given placebo tablets. No changes in intestinal permeability or plasma albumin were observed after deworming. Significant decreases in total protein (P<0.001) and alpha(1)-antichymotrypsin (P<0.001) were observed in the treatment group, indicating possible reductions in inflammation and immunoglobulin concentration after deworming. A significant increase in the prevalence of Giardia intestinalis (from 4% to 49%) in the treatment group was associated with a short-term reduction in weight (P = 0.02) and higher intestinal permeability (P <0.001) in infected subjects. No long-term effects of G. intestinalis on growth were observed. CONCLUSION Low-intensity helminth infections, predominantly of A. lumbricoides and T. trichiura, do not contribute significantly to the poor growth and biochemical status of rural Bangladeshi children.
Collapse
Affiliation(s)
- C A Northrop-Clewes
- Human Nutrition Research Group, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, United Kingdom
| | | | | | | |
Collapse
|
30
|
Abstract
The relationship between intestinal pathology and immune expulsion of gastrointestinal nematodes remains controversial. Parasite expulsion is associated with intestinal pathology in several model systems and both of these phenomena are T cell dependent. However, while immune expulsion of gastrointestinal helminth parasites is usually associated with Th2 responses, the effector mechanisms directly responsible for parasite loss have not been elucidated. In contrast, the intestinal pathology observed in many other disease models closely resembles that seen in helminth infections, but has been attributed to Th1 cytokines. We have used infection with the nematode Trichinella spiralis in mice defective for cytokines to demonstrate that although parasite expulsion is indeed IL-4 dependent, contrary to expectations, the enteropathy is also regulated by IL-4. Furthermore, abrogation of severe pathology in iNOS deficient and TNF receptor defective animals does not prevent parasite expulsion. TNF and iNOS are therefore involved in intestinal pathology in nematode infections, apparently under regulation by IL-4 and Th2 mediated responses. Therefore, it appears that the IL-4-dependent protective response against the parasite operates by a mechanism other than merely the gross degradation of the parasite's environment brought about by the immune enteropathy. However, it remains important to elucidate the protective mechanisms involved in parasite expulsion, which are still unclear.
Collapse
Affiliation(s)
- P Garside
- Department of Immunology and Bacteriology, University of Glasgow, Western Infirmary, Glasgow, UK
| | | | | | | |
Collapse
|
31
|
Hotez PJ. Pediatric geohelminth infections: Trichuriasis, ascariasis, and hookworm infections. ACTA ACUST UNITED AC 2000. [DOI: 10.1053/spid.2000.9637] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
32
|
Duff EM, Anderson NM, Cooper ES. Plasma insulin-like growth factor-1, type 1 procollagen, and serum tumor necrosis factor alpha in children recovering from Trichuris dysentery syndrome. Pediatrics 1999; 103:e69. [PMID: 10224213 DOI: 10.1542/peds.103.5.e69] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES To explore: 1) the relationship between plasma insulin-like growth factor-1 (IGF-1) and other markers of growth; and 2) the effect of serum concentrations of tumor necrosis factor alpha (TNF) on growth variables in children (2-10 years) stunted by Trichuris dysentery syndrome (TDS), recovering cases, and their matched controls. METHOD Fourteen patients with TDS were admitted to the Tropical Metabolism Research Unit, treated with albendazole and iron, and then followed with matched controls (n = 28) for 1 year. Anthropometric and biochemical measurements were done on admission and then every 3 months for the year. Plasma IGF-1, the carboxyterminal propeptide of type 1 procollagen, serum TNF, total serum protein, serum albumin, and complete blood count were determined. RESULTS Low admission plasma levels of IGF-1 in TDS cases were accompanied by high serum levels of TNF, and total serum protein, normal serum albumin, low hemoglobin, reduced collagen synthesis (low plasma carboxyterminal propeptide of type 1 procollagen), and growth failure. These variables improved significantly after treatment. Plasma levels of IGF-1 were significantly related to the Z-scores for height-for-age (r = 0.60, 0.73, 0.68) and weight-for-age (r = 0.69, 0.80, 0.69) of cases and controls, height-for-age (r = 0.51, 0.52, 0.54) and weight-for-age (r = 0.51, 0.52, 0.54) at each measurement throughout the year. Serum levels of TNF were not related to any of the growth variables. CONCLUSION These findings may contribute to the understanding of growth failure in children affected by other forms of chronic inflammatory bowel disease.
Collapse
Affiliation(s)
- E M Duff
- Tropical Metabolism Research Unit, University of the West Indies, Mona, Kingston 7, Jamaica, West Indies.
| | | | | |
Collapse
|
33
|
Tsuyuoka R, Bailey JW, Nery Guimarães AM, Gurgel RQ, Cuevas LE. Anemia and intestinal parasitic infections in primary school students in Aracaju, Sergipe, Brazil. CAD SAUDE PUBLICA 1999; 15:413-21. [PMID: 10409794 DOI: 10.1590/s0102-311x1999000200026] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Anemia is estimated to affect half the school-age children and adolescents in developing countries. The main causes are parasitic infections, malaria, and low iron intake. This study aimed to describe the prevalence of anemia, parasitic infections, and nutritional status of children attending public primary schools in Aracaju, Northeast Brazil. Of 360 students, 26.7% were anemic, and prevalence was higher in children under 8 and over 15 years of age. Overall prevalence of intestinal parasites was 42%, with Ascaris lumbricoides (28.7%), Trichuris trichiura (15.6%), and hookworm (1. 7%) most frequently found. There was an association between parasitic infections and poor sanitary conditions, but there was no association between anemia and presence of intestinal parasites. Height-for-age Z scores were lower than the NCHS standard, and prevalence of stunting was 5.4%. Although intestinal parasites were not associated with anemia, children with parasites had lower nutritional indices (weight- and height-for-age Z scores) than those without parasites.
Collapse
Affiliation(s)
- R Tsuyuoka
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | | | | | | | | |
Collapse
|
34
|
Saldiva SR, Silveira AS, Philippi ST, Torres DM, Mangini AC, Dias RM, da Silva RM, Buratini MN, Massad E. Ascaris-Trichuris association and malnutrition in Brazilian children. Paediatr Perinat Epidemiol 1999; 13:89-98. [PMID: 9987788 DOI: 10.1046/j.1365-3016.1999.00145.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This work was designed to evaluate the role of intestinal parasites on nutritional status in three rural areas of Brazil. A total of 520 children aged 1-12 years were studied through a questionnaire concerning housing, socio-economic conditions and a 24-h food intake recall. Measurements of weight and height were also performed, and three stool samples were collected on consecutive days for parasitological analysis. Scores of the standard deviation (z-scores) for the weight-for-height and height-for-age were used to characterise the growth profile. A high prevalence of intestinal parasites was detected, with Giardia lamblia (44%), Endolimax nana (43%), Ascaris lumbricoides (41%) and Trichuris trichiura (40%) being the most prevalent. Eleven per cent of the children were classified as showing stunting. Inadequate daily caloric intake was observed in 78% of the population and the proportion of those with inadequate protein intake was 34%. Logistic regression analysis was employed for the multivariate study. Stunting was significantly associated with estimators of low economic income, inadequate protein intake and polyparasitism, especially the association between Ascaris lumbricoides and Trichuris trichiura.
Collapse
Affiliation(s)
- S R Saldiva
- School of Medicine, University of São Paulo, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Abstract
The relationship between intestinal pathology and immune expulsion of gastrointestinal nematodes remains controversial. Parasite expulsion is associated with intestinal pathology in several model systems and both of these phenomena are T cell dependent. Immune expulsion of gastrointestinal helminth parasites is usually associated with Th2 responses, but the effector mechanisms directly responsible for parasite loss have not been elucidated. In contrast, the intestinal pathology observed in many other disease models closely resembles that seen in helminth infections, but has been attributed to Th1 cytokines. We have used infection with the nematode Trichinella spiralis in mice defective for cytokines or their receptors to investigate cytokine regulation of both immunopathology and parasite rejection. Consistent with previous findings, we found that parasite expulsion is IL-4 dependent. Contrary to expectations, however, the enteropathy is not regulated by IFN-gamma but by IL-4. Moreover, abrogation of severe pathology in TNF receptor-defective animals does not prevent parasite expulsion. TNF is therefore involved in intestinal pathology in nematode infections, apparently under regulation by IL-4- and Th2-mediated responses. This work therefore not only reveals a novel interplay between IL-4 and TNF, but also that the IL-4-dependent protective response against the parasite operates by a mechanism other than merely the gross degradation of the parasite's environment brought about by the immune enteropathy.
Collapse
Affiliation(s)
- C E Lawrence
- Division of Infection and Immunity, Institute of Biomedical and Life Sciences, University of Glasgow, GB.
| | | | | | | | | | | |
Collapse
|
36
|
Drake LJ, Barker GC, Korchev Y, Lab M, Brooks H, Bundy DA. Molecular and functional characterization of a recombinant protein of Trichuris trichiura. Proc Biol Sci 1998; 265:1559-65. [PMID: 9744108 PMCID: PMC1689327 DOI: 10.1098/rspb.1998.0472] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The pore-forming protein of the human whipworm, Trichuris trichiura, has been postulated to facilitate invasion of the host gut and enable the parasite to maintain its syncytial environment. The data presented here describe the first, to our knowledge, molecular characterization of a pore-forming protein in any helminth and provide a unique demonstration of the functional interaction between a parasite antigen and host molecules. Immunological screening of a T. trichiura cDNA library with T. trichiura infection sera identified a clone of 1.4 kB, the cDNA consisting of 1495 base pairs encoding a protein of 50 kDa. The sequence has a highly repetitive nature containing nine four-disulphide-bonded core domains. Structural prediction analyses reveals an amphipathic nature. TT50 induced pore formation in bilayers in a manner identical to that of the native protein. IgG antibody isolated from T. trichiura infection serum was observed to abolish channel activity.
Collapse
Affiliation(s)
- L J Drake
- Wellcome Trust Centre for the Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, UK
| | | | | | | | | | | |
Collapse
|
37
|
Cooper ES, Ramdath DD, Whyte-Alleng C, Howell S, Serjeant BE. Plasma proteins in children with trichuris dysentery syndrome. J Clin Pathol 1997; 50:236-40. [PMID: 9155675 PMCID: PMC499819 DOI: 10.1136/jcp.50.3.236] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
AIMS To determine whether in Trichuris trichiura dysentery there is (1) evidence of a systemic inflammatory response, (2) evidence that the plasma protein disturbance has special characteristics compared with uninfected children in the endemic environment. METHODS Three groups of children (age 1.6 to 11.4 years) were studied: 53 cases of trichuris dysentery syndrome (TDS), 16 cases of chronic non-secretory diarrhoea not infected with the parasite ("disease controls", DC), and 20 asymptomatic, parasite-free primary schoolchildren (normal controls, NC). C reactive protein, alpha 1 antitrypsin, caeruloplasmin, albumin, total globulin, fibrinogen, fibronectin, ferritin, and transferrin were measured on a single occasion for each. The study was thus a cross sectional descriptive survey for group comparison. Plasma viscosity was measured on admission for TDS and DC and repeated after six weeks and six months for TDS. RESULTS Plasma C reactive protein, alpha 1 antitrypsin, total globulin, fibronectin, and viscosity were significantly higher in TDS than in NC. DC children also had acute phase protein elevations (C reactive protein, caeruloplasmin, viscosity). However, the increase in caeruloplasmin was specific to the DC group while an increase in fibronectin was specific to the TDS group. Serial measurement of viscosity in TDS showed a modest but significant fall during the six months following treatment. CONCLUSIONS There is an acute phase response in intense trichuriasis and a specific elevation of plasma fibronectin. Plasma viscosity remains abnormally high six months after treatment, although lower than at diagnosis.
Collapse
Affiliation(s)
- E S Cooper
- Tropical Metabolism Research Unit, University of the West Indies, Kingston, Jamaica, West Indies
| | | | | | | | | |
Collapse
|
38
|
Grencis RK, Cooper ES. Enterobius, trichuris, capillaria, and hookworm including ancylostoma caninum. Gastroenterol Clin North Am 1996; 25:579-97. [PMID: 8863041 DOI: 10.1016/s0889-8553(05)70264-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Infections by the nematodes Enterobius, Trichuris, Capillaria, and hookworm are some of the most widespread gastrointestinal infections worldwide. This article is designed not only to provide an overview of the different parasites in terms of epidemiology, clinical manifestation, and disease but also to highlight particular areas of intensive research activity that are providing new insights into both the biology of the host-parasite relationship and possible new approaches to infection management for the future.
Collapse
Affiliation(s)
- R K Grencis
- School of Biological Sciences, University of Manchester, United Kingdom
| | | |
Collapse
|
39
|
Affiliation(s)
- S Strobel
- Institute of Child Health, Great Ormond Street Hospital for Children NHS Trust, London, UK
| |
Collapse
|
40
|
Simeon DT, Grantham-McGregor SM, Wong MS. Trichuris trichiura infection and cognition in children: results of a randomized clinical trial. Parasitology 1995; 110 ( Pt 4):457-64. [PMID: 7753585 DOI: 10.1017/s0031182000064799] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effects of mild to moderate infections of Trichuris trichiura on cognitive functions were investigated in Jamaican children aged 7 to 10 years. In all, 189 infected children and 100 uninfected classmates were studied. The infected children were randomly assigned to receive treatment (albendazole) or a placebo. All children were given cognitive tests on enrolment and 14 weeks later. These included verbal fluency (generation of ideas), digit span (working memory), number choice (speed of processing of visual stimuli), visual search (sustained attention) and a French Vocabulary test (paired-associate learning). At baseline, the infected children had lower scores than the uninfected ones in fluency (P = 0.01), search (P = 0.02) and French (P = 0.01). Treatment effects were examined among infected children and there was no significant treatment effect for any of the tests. However, there was a significant treatment by weight-for-age interaction in fluency (P < 0.05). The children with low weight-for-age (Z-score < -1) improved with treatment while there was no improvement with treatment among the other children. We concluded that treatment of children with mild to moderate T. trichiura infections using albendazole produces little benefit in cognition if they are adequately nourished; however, undernourished children are more likely to benefit.
Collapse
Affiliation(s)
- D T Simeon
- Tropical Metabolism Research Unit, University of the West Indies, Kingston, Jamaica
| | | | | |
Collapse
|
41
|
Ramdath DD, Simeon DT, Wong MS, Grantham-McGregor SM. Iron status of schoolchildren with varying intensities of Trichuris trichiura infection. Parasitology 1995; 110 ( Pt 3):347-51. [PMID: 7724242 DOI: 10.1017/s0031182000080938] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The relationship between varying intensities of Trichuris trichiura infection and iron status was examined in Jamaican schoolchildren, aged 7 to 11 years. A total of 409 children was identified with T. trichiura (epg > 1200). A control group comprised 207 uninfected children who were matched by school and class to every pair of infected subjects. Blood samples were obtained from 421 children: 264 infected and 157 controls. Compared to the rest of the children, those with heavy infections (epg > 10,000) had significantly lower (P < 0.05) Hb (11.5 +/- 1.3 vs. 12.1 +/- 1.1 g/dl), MCV (78.6 +/- 6.3 vs. 81.2 +/- 5.5 fl), MCH (26.2 +/- 2.9 vs. 27.5 +/- 2.5 pg) and MCHC (33.2 +/- 1.5 vs. 33.9 +/- 1.4 g/dl). Similarly, the prevalence of anaemia (Hb < 11.0 g/dl) amongst heavily infected children (33%) was significantly higher (P < 0.05) than the rest of the sample (11%). These differences remained significant after controlling for confounding variables including socio-economic status, age, gender, area of residence and the presence of Ascaris infections. Differences in red cell count, ferritin, and free erythrocyte protoporphyrin were not statistically significant and showed no association with the infectious load. These results suggest that in the Jamaican children studied, iron deficiency anemia is associated with Trichuris infections over 10,000 epg, but not with less intense infections.
Collapse
Affiliation(s)
- D D Ramdath
- Tropical Metabolism Research Unit, University of the West Indies, Mona, Kingston, Jamaica
| | | | | | | |
Collapse
|
42
|
Chapman RS, Cooper KD, De Fabo EC, Frederick JE, Gelatt KN, Hammond SP, Hersey P, Koren HS, Ley RD, Noonan F. Solar ultraviolet radiation and the risk of infectious disease: summary of a workshop. Photochem Photobiol 1995; 61:223-47. [PMID: 7716186 DOI: 10.1111/j.1751-1097.1995.tb03966.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- R S Chapman
- U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
| | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Lillywhite JE, Cooper ES, Needham CS, Venugopal S, Bundy DA, Bianco AE. Identification and characterization of excreted/secreted products of Trichuris trichiura. Parasite Immunol 1995; 17:47-54. [PMID: 7731735 DOI: 10.1111/j.1365-3024.1995.tb00965.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This study provides the first description of the range and immunogenicity of proteins excreted and/or secreted by living T. trichiura adult worms following their recovery from the human large intestine. Metabolic labelling of T. trichiura excretory/secretory (ES) products with [35S]-methionine revealed a range of proteins with prominent components at 52-54 kDa, 35-45 kDa & 17 kDa. In contrast, the major component of unlabelled T. trichiura ES, somatic whole worm and isolated stichosome extracts, and of [35S]-methionine labelled somatic extracts, was present at approximately 47 kDa. Similarly, the major 43 kDa protein present in unlabelled T. muris ES, somatic worm extract and [35S]-methionine labelled somatic worm extract, was only weakly detected in labelled T. muris ES. Pulse chase experiments demonstrated that after 20 h, the 43 kDa was a prominent component of T. muris ES. These data suggest that the 43/47 kDa protein of Trichuris adult worms is not a major constituent of newly synthesized ES but is either synthesized at a slower rate than other proteins, or sequestered or stored, most likely in the stichocytes, before release. Immunoprecipitations using a range of sera from T. trichiura-infected individuals demonstrated that many of the ES components are immunogenic. Antibody responses were vigorous in children with intense infections and negligible in parasitologically negative children. There was marked heterogeneity in responses to a 17 kDa antigen, with the age profile of anti-17 kDa antibody levels reflecting age-dependent infection intensities at the population level.
Collapse
Affiliation(s)
- J E Lillywhite
- Wellcome Research Centre for Parasitic Infections, Department of Biology, Imperial College, London, UK
| | | | | | | | | | | |
Collapse
|
44
|
Drake LJ, Bianco AE, Bundy DA, Ashall F. Characterization of peptidases of adult Trichuris muris. Parasitology 1994; 109 ( Pt 5):623-30. [PMID: 7831097 DOI: 10.1017/s0031182000076502] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Excretory/secretory (E/S) material of Trichuris muris was found to contain 2 major peptidases, M(r) 85 and 105 kDa, which degrade gelatin optimally at pH 6.0 in sodium dodecyl sulphate-polyacrylamide gels. The peptidases were inactivated by diisopropylfluorophosphate, leupeptin and soybean trypsin inhibitor, but were unaffected by inhibitors of aspartic-, cysteine- and metallo-peptidases, indicating that they are serine peptidases. Both enzymes were detectable within 5 h after incubation of worms in culture medium and showed a time-dependent increase in levels. Neither peptidase was detected in worm extracts, suggesting that they are activated during or following secretion from worms. Live worms degraded a radio-isotope labelled extracellular matrix protein substratum derived from mammalian cells. Aminopeptidase activities capable of catalysing hydrolysis of amino acyl aminomethylcoumarin (MCA) substrates and a Z-Phe-Arg-MCA-hydrolysing cysteine peptidase activity, were detected in extracts of adult worms but not in E/S material.
Collapse
Affiliation(s)
- L J Drake
- Department of Biology, Imperial College of Science, Technology and Medicine, Prince Consort Road, South Kensington, London
| | | | | | | |
Collapse
|
45
|
Abstract
Heavy infection with the geohelminth Trichuris trichiura causes the Trichuris dysentery syndrome (TDS). Growth retardation and anaemia are characteristic of TDS and both are associated with poor development. We have examined the growth and developmental responses to treatment in 19 children aged 27-84 months with TDS. Developmental levels (DQ) were measured with the Griffiths mental development scales. Compared with a control group matched for age, gender and neighbourhood, the TDS children initially had serious deficits in DQ (24 points, p < 0.001). After a year of anthelmintic treatment, the TDS children showed improvement in locomotor development (p < 0.001) compared with the controls. The TDS children also had initial deficits in height-for-age, weight-for-height, mid-upper arm circumference and haemoglobin levels. They caught up rapidly in indices of wasting (weight-for-height and mid-upper arm circumference) and showed steady improvement in height-for-age and haemoglobin levels. Catch-up in height was comparable to that of children recovering from coeliac disease. The importance of continuing prevention after initial treatment is highlighted.
Collapse
Affiliation(s)
- J E Callender
- Tropical Metabolism Research Unit, University of the West Indies, Mona, Kingston, Jamaica
| | | | | | | |
Collapse
|
46
|
Drake L, Korchev Y, Bashford L, Djamgoz M, Wakelin D, Ashall F, Bundy D. The major secreted product of the whipworm, Trichuris, is a pore-forming protein. Proc Biol Sci 1994; 257:255-61. [PMID: 7991635 DOI: 10.1098/rspb.1994.0123] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The data presented here describe the first unequivocable characterization of a pore-forming protein in any helminth parasite. The excretory/secretory (E/S) material of the human whipworm T. trichiura contains a highly abundant protein of molecular mass 47 kDa (TT47); the murine model parasite, T. muris, contains a similarly abundant protein of molecular mass 43 kDa (TM43). When purified to homogeneity, these proteins induce ion-conducting pores in lipid bilayers. Antibodies raised against TM43 abolish channel activity. Pore formation in epithelial cell membranes may facilitate invasion of the host gut by Trichuris and enable the parasite to maintain its syncytial environment in the caecal epithelium. The observation that this activity may be inhibited by antibody opens a possible avenue for drug and vaccine development.
Collapse
Affiliation(s)
- L Drake
- Department of Biology, Imperial College of Science, Technology & Medicine, South Kensington, London, U.K
| | | | | | | | | | | | | |
Collapse
|
47
|
Needham CS, Lillywhite JE. Immunoepidemiology of intestinal helminthic infections. 2. Immunological correlates with patterns of Trichuris infection. Trans R Soc Trop Med Hyg 1994; 88:262-4. [PMID: 7974658 DOI: 10.1016/0035-9203(94)90071-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The significance of parasite-specific serum and secretory immunoglobulin (Ig) isotype responses as determinants of Trichuris trichiura infection intensity in endemic communities is discussed. Comparison of age-dependent isotype responses and the age profiles of infection intensity in 2 endemic communities with markedly different levels of T. trichiura transmission suggest that serum IgA responses may reflect the accumulated past experience of infection and thus may be relevant in acquired immunity to T. trichiura and contribute to the age-convexity of infection intensity in areas of intense transmission. Preliminary analysis of data from a second community-based study shows that parasite-specific secretory IgA in saliva increases with age and correlates negatively with infection intensity, suggesting that secretory IgA may also be implicated in acquired immunity to this gut-dwelling nematode.
Collapse
Affiliation(s)
- C S Needham
- Department of Biology, Imperial College of Science, Medicine and Technology, London, UK
| | | |
Collapse
|
48
|
Jenkins D, Wakelin D. Immunoepidemiology of intestinal helminth infections. 4. Immunopathology in trichuriasis: lessons from the mouse model. Trans R Soc Trop Med Hyg 1994; 88:269-73. [PMID: 7974660 DOI: 10.1016/0035-9203(94)90074-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The severity and consequences of human Trichuris infection vary widely. This may reflect differences in immune response. T. muris is a natural parasite of mice which provides a close, well defined, easily manipulated model for otherwise uninvestigatable aspects of this response. Normal mice reject the parasite in 3 weeks, but mice subjected to transient immunosuppression around the time of infection develop a persistent caecal infection. Sequential histopathological studies have shown that infected, normal mice develop a marked intraepithelial, mucosal, 'globule leucocyte' response, accompanied by low-level lymphocytic and histiocytic responses in the lamina propria. The reaction is maximal at 3 weeks and declines towards normal after rejection. Infected, immunosuppressed mice show a slower response with, by weeks 4 and 5, fewer 'globule leucocytes', but a chronic colitis comprising heavy, mixed, mucosal and submucosal inflammation and crypt damage accompanied by persistent parasite infection. The 'globule leucocyte' has been characterized by cytochemistry and electron microscopy as having a mast cell origin. This study, with other evidence, suggests that the replacement of a Th2 (allergic) T helper cell response by a Th1 (cell-mediated) response may result in increased severity and persistence of colitis in response to Trichuris infection.
Collapse
Affiliation(s)
- D Jenkins
- Department of Pathology, Queen's Medical Centre, University of Nottingham, UK
| | | |
Collapse
|
49
|
Bundy DA. Immunoepidemiology of intestinal helminthic infections. 1. The global burden of intestinal nematode disease. Trans R Soc Trop Med Hyg 1994; 88:259-61. [PMID: 7974657 DOI: 10.1016/0035-9203(94)90069-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Estimates of the world-wide prevalence of intestinal nematode infections indicate that there are more than 1000 million people infected, and several million cases of clinical helminthiases. Recent studies suggest that the morbidity has been underestimated and that moderate intensities of infection may have important developmental consequences, particularly for children of school age.
Collapse
Affiliation(s)
- D A Bundy
- Biology Department, Imperial College of Science, Technology and Medicine, London, UK
| |
Collapse
|
50
|
Callender J, Grantham-McGregor S, Walker S, Cooper E. Developmental levels and nutritional status of children with the Trichuris dysentery syndrome. Trans R Soc Trop Med Hyg 1993; 87:528-9. [PMID: 7505495 DOI: 10.1016/0035-9203(93)90074-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Affiliation(s)
- J Callender
- Tropical Metabolism Research Unit, University of the West Indies, Mona, Kingston, Jamaica
| | | | | | | |
Collapse
|