A field and a household survey, the latter of which included inspections and interviews with the residents of a total
of 1370 properties, were conducted in 2004 in 30 villages of the city of Luang Prabang, Lao PDR, in order to assess
the degree of rodent infestation and to identify potential factors influencing infestations. Roof rats, Rattus rattus,
and the Polynesian rat, Rattus exulans, were the only rodents found in the city, and trapping results showed a clear
dominance of roof rats (80–90% of all individuals). Measurements of rodent activity using tracking patches
correlated positively with the trapping data, and revealed a significantly higher degree of rat infestation during the
rainy season (September) than during the dry season (November). If households in the vicinity of the sampling
locations were considered, villagers’ accounts of indoor rodent infestations recorded during the household survey
correlated positively with measurements of rodent activity. At least every second household reported indoor
infestations. Using explorative statistical analyses (classification trees, factor analysis) we checked the predictive
or explanatory value of up to 28 variables assessed during household inspections for villagers’ observations on
rodent infestation as the dependent variable. Trophic factors such as exposed food (indoors) and garbage (outdoors),
and structural features such as open ceilings (indoors) and rat harborage in gardens (outdoors) ranked highest as
explanatory variables. Assessment of a small sample of roof rat droppings collected inside houses revealed the
presence of the potential disease agents Salmonella javiana, Cryptosporidium parvum, Giardia duodenalis and the
parasitic nematode Calodium hepaticum (syn. Capillaria hepatica). These results underline the need for an
appropriate rodent management strategy for the city, whereby simple sanitation and rodent-proofing measures
could be cheap means of reducing rat infestation rates.