Animal research plays an important role in the pre-clinical phase of clinical trials. In animal studies, the power analysis approach to sample size calculation is recommended. Whenever it is not possible to assume the standard deviation and the effect size, an alternative to the power analysis approach is the 'resource equation' approach, which sets the acceptable range of the error degrees of freedom (DF) in an analysis of variance (ANOVA). The aim of this article is to guide researchers in calculating the minimum and maximum numbers of animals required in animal research by reformulating the error DF formulas.

BackgroundIn Malaysia, leptospirosis is considered an endemic disease, with sporadic outbreaks following rainy or flood seasons. The objective of this study was to develop and validate a new knowledge, attitude, belief and practice (KABP) questionnaire on leptospirosis for use in urban and rural populations in Malaysia.MethodsThe questionnaire comprised development and validation stages. The development phase encompassed a literature review, expert panel review, focus-group testing, and evaluation. The validation phase consisted of exploratory and confirmatory parts to verify the psychometric properties of the questionnaire. A total of 214 and 759 participants were recruited from two Malaysian states, Kelantan and Selangor respectively, for the validation phase. The participants comprised urban and rural communities with a high reported incidence of leptospirosis. The knowledge section of the validation phase utilized item response theory (IRT) analysis. The attitude and belief sections utilized exploratory factor analysis (EFA) and confirmatory factor analysis (CFA).ResultsThe development phase resulted in a questionnaire that included four main sections: knowledge, attitude, belief, and practice. In the exploratory phase, as shown by the IRT analysis of knowledge about leptospirosis, the difficulty and discrimination values of the items were acceptable, with the exception of two items. Based on the EFA, the psychometric properties of the attitude, belief, and practice sections were poor. Thus, these sections were revised, and no further factor analysis of the practice section was conducted. In the confirmatory stage, the difficulty and discrimination values of the items in the knowledge section remained within the acceptable range. The CFA of the attitude section resulted in a good-fitting two-factor model. The CFA of the belief section retained low number of items, although the analysis resulted in a good fit in the final three-factor model.ConclusionsBased on the IRT analysis and factor analytic evidence, the knowledge and attitude sections of the KABP questionnaire on leptospirosis were psychometrically valid. However, the psychometric properties of the belief section were unsatisfactory, despite being revised after the initial validation study. Further development of this section is warranted in future studies.

This study revealed a possible high seroprevalence of leptospirosis among febrile cases, indicating the need to review the importance of adding leptospirosis to the case investigation of febrile illness, especially among high-risk occupational groups in Malaysia, as well as in other endemic countries.

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ObjectivesTo determine the leptospirosis seroprevalence and to identify the predominant infecting serovars among oil palm plantation workers.MethodsThe cross-sectional study involved 350 asymptomatic oil palm plantation workers in Melaka and Johor. A serological test using the microscopic agglutination test was conducted in the Institute of Medical Research with a cut-off titre for seropositivity of ≥1:100.ResultsThe overall seroprevalence of leptospiral antibodies was 28.6%. The job category with the highest seroprevalence was the fruit collector with 59.2%. The predominant serovar identified was serovar Sarawak (Lepto 175) (62%).ConclusionA high seroprevalence of leptospiral antibodies was detected among oil palm plantation workers and specifically among fruit collectors. The predominant infecting serovar among the workers was serovar Sarawak (Lepto 175). The findings suggest that more studies are needed to determine the reasons for the high seroprevalence and the transmission and pathogenicity of the local serovar Sarawak (Lepto 175).