Review articleCould control of soil-transmitted helminthic infection influence the HIV/AIDS pandemic
Introduction
Helminthiasis has been present throughout the evolution of humans, whereas HIV/AIDS is a new disease. Research on the potential for interaction between them is at an early stage. Endemicity of both diseases is enhanced by overcrowding and poverty (Markus and Fincham, 2000a). This reality exists in many countries and coincidentally increases the probability of interaction. It follows that, since the human immunodeficiency virus (HIV) causes immunosuppression, it is possible that soil-transmitted helminths (S-THs), which, are also called geohelminths, might be amongst opportunists that take advantage of hosts which, are compromised in this way. However, a more serious possibility is that of a reversed relationship. Is HIV the opportunist taking advantage of immunological host–parasite relationships that have stabilised as a result of evolution (Maizels et al., 1993, Maizels et al., 1999, Finkelman and Urban, 2001, Pritchard and Brown, 2001, Viney, 2002) and long before HIV/AIDS became a disease? This review summarises evidence for the possibility of opportunistic infection in both directions.
The gravity of the HIV/AIDS situation is illustrated by the fact that in South Africa, it has been estimated that the disease will kill between five and seven million adults between 15 and 40 years of age, by 2010 (Dorrington et al., 2001). In addition, large numbers of children are dying or being orphaned. The total population of South Africa is currently about 43 million people. In December 2001, UNAIDS estimated that 40 million individuals globally were living with HIV/AIDS and that 20 million had died of AIDS-related diseases (UNAIDS, 2001).
Section snippets
Literature review
The focus in this review is on infection of humans by those S-THs that are of public health importance in developing countries. They are Ascaris lumbricoides, the hookworms Necator americanus and Ancylostoma duodenale, Trichuris trichiura, and Strongyloides stercoralis. S. stercoralis is included because infection is related to conditions of poverty, overcrowding and lack of hygiene and sanitation (Roberts and Janovy, 2000). In such situations, the prevalence can exceed 50% (Mahmoud, 1996).
Discussion
The information summarised in Table 1, Table 2, Table 3, Table 4, Table 5, Table 6, Table 7, Table 8, Table 9, Table 10, Table 11, Table 12 indicates that the chronic immune response to helminthiasis could be adversely influencing the epidemics of HIV/AIDS and TB. Therefore, it is imperative to test the hypothesis that prevention and/or treatment of helminthic infections may improve the situation (Barouch and Letvin, 2001). Research should seek to define changes in the immune profile and plasma
References (113)
- et al.
Th1–Th2: reliable paradigm or dangerous dogma
Immunol. Today
(1997) Immunomodulation by nematodes: a review
Vet. Parasitol.
(1984)- et al.
The role of eosinophils in parasitic helminth infections: insights from genetically modified mice
Parasitol. Today
(2000) Do hookworm elicit protective immunity in man
Parasitol. Today
(1987)Good worms or bad worms: do worm infections affect the epidemiological patterns of other diseases
Parasitol. Today
(2000)- et al.
Immune activation is a dominant factor in the pathogenesis of African AIDS
Immunol. Today
(1995) - et al.
Can eradication of helminthic infections change the face of AIDS and tuberculosis
Immunol. Today
(1999) - et al.
Immunity to helminths: ready to tip the biochemical balance
Parasitol. Today
(1992) - et al.
Good worms or bad worms: do worm infections affect the epidemiological patterns of other diseases
Parasitol. Today
(2000) - et al.
Lineage-specific expression of human immunodeficiency virus (HIV) receptor/coreceptors in differentiating hematopoietic precursors: correlation with susceptibility to T- and M-tropic HIV and chemokine-mediated HIV resistance
Blood
(1999)
Prevalence of intestinal parasitic infections in patients with acquired immunodeficiency syndrome in Brazil
Int. J. Infect. Dis.
A Th1–Th2 switch is a critical step in the etiology of HIV infection
Immunol. Today
Towards effective control of Strongyloides stercoralis
Parasitol. Today
Immediate hypersensitivity in the colon of children with chronic Trichuris trichiura infection
Lancet
Inverse association between BCG immunisation and intestinal nematode infestation among HIV-1 positive individuals in Uganda
Lancet
Intestinal nematode parasites, cytokines and effector mechanisms
Int. J. Parasitol.
Immunization with Ascaris suum extracts impairs T cell functions in mice
Cell. Immunol.
Human immune response to Trichuris trichiura
Trends Parasitol.
Regulation and biological function of helminth-induced cytokine responses
Immunol. Today
The other side of the coin: the protective role of the TH2 cytokines
J. Allergy Clin. Immunol.
Eosinophils and AIDS
Med. Hypothesis
Maternal filarial infection as risk factor for infection in children
Lancet
Nippostrongylus brasiliensis: cytokine responses and nematode expulsion in normal and IL-4-deficient mice
Exp. Parasitol.
Comparison of subcutaneous and intravenous interleukin-2 in asymptomatic HIV-1 infection: a randomised controlled trial
Lancet
The link between helminthic infection and atopy
Parasitol. Today
Helminthiasis and HIV vaccine efficacy
Lancet
Implications for neonatal HIV/AIDS and TB of sensitization in utero to helminths
Trends Parasitol.
Experimental infestation with human strain Strongyloides fülleborni in man
Lancet
The survival strategies of hookworms
Parasitol. Today
Is Necator americanus approaching a mutualistic symbiotic relationship with humans
Trends Parasitol.
Evidence for larval hypobiosis in Australian strains of Ancylostoma duodenale
Trans. R. Soc. Trop. Med. Hyg.
Helminth infection results in decreased virus-specific CD8+ cytotoxic T-cell and Th1 cytokine responses as well as delayed virus clearance
Proc. Natl. Acad. Sci. USA
The distribution of helminth infections along the coastal plain of KwaZulu-Natal province, South Africa
Ann. Trop. Med. Parasitol.
Th1 and Th2 cells and immunity to intestinal helminths
Chem. Immunol.
A critical role for Il-13 in resistance to intestinal nematode infection
J. Immunol.
Markus and Fincham raise an important point
Science
Control of viremia and prevention of clinical AIDS in Rhesus monkeys by cytokine-augmented DNA vaccination
Science
Eventual AIDS vaccine failure in a rhesus monkey by viral escape from cytotoxic T lymphocytes
Nature
Lower hookworm incidence, prevalence, and intensity of infection in children with a Bacillus Calmette-Guérin vaccination scar
J. Infect. Dis.
Immune dysregulation in Ethiopian immigrants in Israel: relevance to helminth infections
Clin. Exp. Immunol.
Pathogenesis of AIDS in Africa—lessons from the Ethiopian immigrants in Israel
Immunologist
Eradication of helminthic infections may be essential for successful vaccination against HIV and tuberculosis
Bull. WHO
Chronic immune activation associated with intestinal helminth infections results in impaired signal transduction and anergy
J. Clin. Invest.
The role of interleukin-13 in infectious diseases and allergy
BioEssays
Evaluating measures to control intestinal parasitic infections
World Health Stat. Q.
Intestinal parasites in HIV-seropositive Zambian children with diarrhoea
J. Trop. Pediatr.
Enteric parasites and AIDS
Sao Paulo Med. J.
Eosinophils as host cells for HIV-1
Arch. Virol.
Albendazole treatment of children with ascariasis enhances the vibriocidal antibody response to the live attenuated oral cholera vaccine CVD 103-HgR
J. Infect. Dis.
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