Biocontrol of rats in an urban environment in Southeast Asia using Sarcocystis singaporensis.
BACKGROUND
Upon request of the local administration a control campaign targeting commensal rats (Rattus rattus, R. exulans) was conducted in 30 sub-districts (villages) of the World Heritage town Luang Prabang, Northern Laos, using rat bait containing lethal quantities of the parasitic protist Sarcocystis singaporensis. The associated investigations assessed the short-term control efficacy, willingness of residents to co-operate (community approach), and temporal and spatial changes of the urban rat population in response to treatment.


RESULTS
Biological rodent control significantly reduced rodent activity (percentage of positive tracking patches) in the town, from a mean of 25.3% (±12.8% SD) before (January-February) down to 8.0% (±4.4%) after (June) treatment. Reduction of rodent activity relative to three untreated villages was 83%. Similarly, residents observed significantly fewer rats on their properties after the campaign (mean percentage of households (HHs) per village with sightings), whereby reduction of sightings amounted to 57%. There was significant correlation between residents' observation rates and rodent activity. Among 94 rats trapped before and after treatment each, proportions of adult R. exulans and juvenile R. rattus were higher after rodent control, suggesting that a considerable part of the adult house rat population had been removed. Furthermore, a 5% post-campaign incidence of infection suggested that few rats had survived bait uptake.


CONCLUSION
S. singaporensis may be used successfully as tactical biocontrol agent for culling of rats in urban environments. We propose additional components of a long-term rodent management strategy for the town, without which the impact of culling campaigns would be limited. © 2019 Society of Chemical Industry.
['Jäkel|Thomas|T|https://orcid.org/0000-0001-8039-5054', 'Promkerd|Prasartthong|P|', 'Sitthirath|Rasmy|R|', 'Guedant|Pierre|P|', 'Khoprasert|Yuvaluk|Y|']
D000818:Animals D002947:Cities D007812:Laos D010572:Pest Control, Biological D051381:Rats D012522:Sarcocystis
biocontrol Sarcocystis singaporensis Rattus rattus northern Laos biological rodent control Rattus exulans Rattus tanezumi town of Luang Prabang urban rodent control