Prevalence of infection, mean worm burden and degree of worm aggregation as determinants of prevalence of disease due to intestinal helminths.
Arch Med Res
; 28(1): 121-7, 1997.
Article
em En
| MEDLINE
| ID: mdl-9078599
Theoretical predictions of disease prevalence due to helminth infections based upon a simple probabilistic model which considers the infection prevalence, the mean worm burden and the degree of worm aggregation are presented. A numerical reappraisal of the likely estimates of the degree of aggregation based upon maximum likelihood estimates of the negative binomial distribution is presented. The prevalence of disease shows a positive relationship with the mean worm burden. This association is hyperbolic when helminth parasites are severely aggregated but is s-shaped when helminth parasites tend to be overdispersed. The prevalence of disease decreases with the degree of worm aggregation when the values of the mean intensity are low; as the mean intensity increases this association becomes positive. The relationship between prevalence of disease and prevalence of infection is hyperbolic for severe degrees of parasite aggregation and is s-shaped for intermediate degrees of aggregation. However, if the mean intensity is low and the degree of aggregation is high there could be a negative relationship between the prevalence of disease and the prevalence of infection. The presence of disease due to helminth parasites is feasible for determined ranges of values of the infection prevalence, mean intensity and the degree of worm clumping.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Helmintíase
/
Helmintos
/
Enteropatias Parasitárias
Tipo de estudo:
Prevalence_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Animals
/
Humans
País/Região como assunto:
Mexico
Idioma:
En
Revista:
Arch Med Res
Assunto da revista:
MEDICINA
Ano de publicação:
1997
Tipo de documento:
Article
País de publicação:
Estados Unidos