The distribution of the pathogenic nematode Nematodirus battus in lambs is zero-inflated.
Parasitology
; 135(10): 1225-35, 2008 Sep.
Article
em En
| MEDLINE
| ID: mdl-18620622
ABSTRACT
Understanding the frequency distribution of parasites and parasite stages among hosts is essential for efficient experimental design and statistical analysis, and is also required for the development of sustainable methods of controlling infection. Nematodirus battus is one of the most important organisms that infect sheep but the distribution of parasites among hosts is unknown. An initial analysis indicated a high frequency of animals without N. battus and with zero egg counts, suggesting the possibility of a zero-inflated distribution. We developed a Bayesian analysis using Markov chain Monte Carlo methods to estimate the parameters of the zero-inflated negative binomial distribution. The analysis of 3000 simulated data sets indicated that this method out-performed the maximum likelihood procedure. Application of this technique to faecal egg counts from lambs in a commercial upland flock indicated that N. battus counts were indeed zero-inflated. Estimating the extent of zero-inflation is important for effective statistical analysis and for the accurate identification of genetically resistant animals.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Doenças dos Ovinos
/
Infecções por Nematoides
Tipo de estudo:
Health_economic_evaluation
Limite:
Animals
País/Região como assunto:
Europa
Idioma:
En
Revista:
Parasitology
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Reino Unido