Biology Reference
In-Depth Information
that T cells
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and NK cells
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facilitate larval development. Although there
is currently no evidence that the cues governing the development of
nematodes such as Ascaris behave in a similar fashion, it is possible that
pre-existing immune responses in the GI tract may enhance establishment
of an incoming Ascaris via the provision of important growth signals for
newly hatched larvae or larvae undergoing a final molt to the adult form
upon re-entry into the GI tract.
CONCLUDING REMARKS
In 2001, the World Health Assembly resolved to decrease the rates of
morbidity and mortality associated with geohelminths worldwide by
recommending that member states endemic for these infections institute
regular administration of chemotherapeutics to school-aged children. The
goal of this resolution was to achieve consistent treatment of at least 75%
of all school children at risk by 2010
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(see Chapter 15). However, the
impact of this strategy on the pathogenesis of co-infecting pathogens was
not a main consideration.
Over time there have been many articles published discussing the
possible implications of eradication of geohelminths such as Ascaris on
the pathogenesis of co-infecting organisms,
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e
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but a comprehensive
BOX 4.1
SOME AREAS REQUIRING
ELUCIDATION
Infection intensity: Are heavy Ascaris burdens associated with the
presence of co-infecting organisms?
HIV co-infection: Does Ascaris co-infection alter viral loads and/or
the progression of AIDS?
Malaria co-infection: Are protective effects of Ascaris on the devel-
opment of cerebral malaria observed in geographical locations outside
Asia?
Tissue migration: Does tissue containing granulomas from co-infection
with other pathogens (e.g. Schistosoma or tuberculosis) impair or enhance
Ascaris larval migration?
Adult longevity: Do diarrheal-causing pathogens adversely influence
the longevity of adult Ascaris nematodes?
Egg output: Does gastrointestinal immune suppression by HIV
enhance survival or fecundity of Ascaris adult nematodes?
