Situation Analysis of Varroosis and Tropilaelaps Infestation of Honeybees in Thailand, 2017-2018.

Background/aim: To explore the prevalence of Varroa destructor and Tropilaelaps infestation in honeybees in Thailand and investigate factors associated with those diseases.

Methods: A quantitative cross-sectional design was employed during 2017-2018. We sampled 144 apiaries in 13 provinces from the surveillance database of the Department of Livestock Development. In total, 1,152 bee samples were collected. A microscopic exam was performed to assess if each sample was infested with Varroa destructor mites and tropilaelaps mites. A chi-square test and multivariable logistic regression were conducted.

Results: The prevalence of Varroa destructor and Tropilaelaps infestation at the apiary level was 50.69% and 32.64%, respectively. At the beehive level, we found that the prevalence of Varroa destructor infestation was 22.74% while that of Tropilaelaps infestation was 6.94%. The northern region saw the highest prevalence of Varroa destructor and Tropilaelaps infestation. Apiaries that received a "Good Agricultural Practice" (GAP) certificate from the Bureau of Livestock Standards and Certification, demonstrated a 42% lower chance of contracting both parasitic infestations; however, no statistically significant difference was reported. Apiaries that had a history of chemical use showed approximately 2.7 times greater odds of Tropilaelaps infestation (adjusted odds ratio [AOR] = 2.69; 95% confidence interval [CI] = 1.16-6.21) with statistical significance (p = 0.02). The probability of Varroa destructor infestation amongst apiaries with apiary movement was approximately 60% lower than amongst those without apiary movement (AOR = 0.40, 95% CI = 0.20-0.80, p = 0.01).

Conclusion: Varroa destructor and Tropilaelaps infestations are a critical concern for beekeeping in Thailand. Apiary movement tended to lower the risk of Varroa destructor infestation while chemical use tended to enhance the risk of Tropilaelaps infestation. Further studies that allow a more comprehensive collection of determinants of parasitic infestation in honeybees, for instance, apiary cleaning frequency and farm environments (such as temperature and rainfall), are recommended.