Urban livestock production in Cambodia : socio-economic benefits and public health hazards

Abstract: Keeping livestock can make an important contribution to the livelihoods of poor urban dwellers. There are concerns, however, that livestock keeping in and around urban areas may lead to environmental problems and increased incidence of disease transfer between animals and humans (zoonoses). This thesis examined different socio-economic benefits and public health hazards associated with pig keeping in urban and peri-urban areas in a lower middle-income country, using Phnom Penh, the capital of Cambodia, as a case study. Interviews were carried out with householders in Phnom Penh province and faecal samples were collected from their pigs for detection of zoonotic pathogens and for antimicrobial susceptibility analysis of commensal bacteria. All households reported keeping pigs primarily for commercial purposes and the majority (60%) considered pigs to be an important income source for the household. Diseases among the pigs and low revenues were considered main constraints. None of the respondents mentioned any concerns about potential health hazards. The householders reported that pig manure was commonly dumped in the environment (46%) whereas cattle manure was used as a fertiliser (66%) (P < 0.001). Dumping of pig manure was more common in households with lower socio-economic position (P < 0.001) and in households that did not have access to agricultural land (P < 0.001). Antimicrobial use was mainly based on farmers’ own judgement, with 66% of respondents frequently self-adjusting treatment duration and dose. Around 45% had not heard about antimicrobial resistance. Commensal Escherichia coli exhibited high prevalence of resistance to several antimicrobials considered important for human health, and multidrug-resistance was found in 79% of the bacteria isolates. Higher prevalence of resistance was observed on farms that administered prophylactic antimicrobials and on farms that treated the entire group of pigs in the event of disease. In conclusion, although pig keeping was considered an important income source by the households studied, many employed practices that may contribute to pollution and increased health hazards to urban dwellers. For pig keeping continuing to exist in proximity to urban areas in countries like Cambodia, disease prevention interventions and improvements in manure management are needed.

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