Factors explaining the abundance of rodents in the city of Luang Prabang, Lao PDR, as revealed by field and household surveys

Abstract

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.

Global parasite and Rattus rodent invasions: The consequences for rodent‐borne diseases

“…New invasion threats therefore still exist for all the Pacific areas, including the South Japan islands, Australia, New Zealand, New Caledonia and French Polynesia (Russell et al 2008). There is also concerns about the invasion of the northern part of Indochina as R. exulans is currently absent from small villages in north Laos , although it is present in large cities such as Luang Prabang (Promkerd et al 2008). In Southeast Asia mainland, R. exulans is found mostly in houses within villages .…”

Local perception of rodent-associated problems in Sahelian urban areas: a survey in Niamey, Niger

“…It has been shown that popular feelings about rodents and rodent-associated damages may be largely misleading for the design of control strategies per se (Singleton et al 2003b). Nevertheless, a scientific approach to people's perception of such damages may provide indirect yet helpful insights into the overall impact of rodents in the human environment (e.g., Olaseha et al 1994;Diarra 2002;Forst and King 2003;Phu Tuan et al 2003;Sang et al 2003;Makundi et al 2005;Promkerd et al 2008). In turn, it is also very useful for evaluating the degree of knowledge as well as beliefs on rodents by inhabitants: having people well informed and aware is the first step of any efficient rodent control policies (Diarra 2002;Forst and King 2003;Marshall and Murphy 2003;Taylor et al 2008;Yonas et al 2010;Morzillo and Mertig 2011).…”

Rodent control and island conservation.

“…Best results are generally achieved when a combination of techniques is applied (Singleton, 1997) and the choice of techniques depend on ecological issues, agronomy, environmental awareness and socio-cultural considerations. Researchers have clearly demonstrated the relationship between rodent activity and the availability of food sources in urban areas (Figgs, 2011) and highlight that simple sanitation and rodent-proofing measures could be a very cheap means of reducing rat infestation rates (Promkerd et al, 2008). Within agricultural systems, researchers have demonstrated that the ecological based management can increase food production in comparison to farms where conventional management techniques are used (Jacob et al, 2010) and can be more cost-effective than conventional control measures (Brown et al, 2006).…”