Rats and disease:

A growing plague in Africa

Dr S.R. Belmain and A.N. MeyerNatural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK

Zoonosis

World-wide concern on the re-emergence of zoonotic diseases, the expansion of endemicity, new etiologic foci

Urbanisation

Climate change

Increased connectivity

Rural expansion

Sanitation

Rodents act as zoonosis reservoirs and vectors and are hosts to more than 60 diseases that can infect humans

Their commensality can lead to disease epidemics

Rodents cause multiple impacts on people’s lives

Importance of Rodents

Impact of rodents on rural household food security and development of ecologically-based rodent management strategies - recently completed project in Mozambique

Promotion of ecologically-based rodent management - operating in South Africa

Prevention of sanitary risks linked to rodents at the rural/peri-urban interface, RATZOOMAN - operating in Tanzania, Zimbabwe, South Africa, Mozambique

Protecting staple crops in eastern Africa: integrated approaches for ecologically based field rodent pest management, STAPLERAT - recently completed project in Tanzania, Ethiopia, Kenya, Zambia

Rodent projects in Africa

Ecologically-based rodent management

Assess the total impact of rodents on people’s lives

Design and test participatory management strategies

Assess the local communities’ knowledge, attitudes and practice on rodents and their control

Plague, annual outbreaks continue in Mozambique, Tanzania; it persists in the wild in many other countries including the RSA

Leptospirosis, preliminary studies in Mozambique showed infection (IgG) rates of 17% in humans

Disease impacts of rodents on people

Lassa Fever in West Africa, similar viruses present throughout Africa

Toxoplasmosis, studies in Mozambique showed antibodies (IgM) present in 88% of human samples

Haemorrhagic fevers, leishmaniasis, salmonella, typhus, parasites,

Potential Control Strategies in Zambezia

Rats are the main source of available protein

Rodenticides are not available, their introduction would be inappropriate

Environmental management

Trapping

Roof management

Comparison between the number of rodents caught in houses trapping daily with ten traps (treatment) and houses with no rodent management activity (non-treatment) in Pinda village, Morrumbala, Zambezia Province. Non-treatment houses trap for three nights only with different houses used each month.

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Treatment (n = 200) Non-treatment (n = 30)

Impact of trapping upon people’s livesBefore 10% of people recently bitten by rat during the night

Storage losses estimated at 200-300Kg/household/year (up to 30% of total household stock)

Leptospirosis (active IgG) prevalence of 17%, plague exposure prevalence of 33%

After 0% rodent bites in last six months

Loss assessment trial indicated losses reduced by 50-60%, duration of food remaining in store increased by about 3 months

Active antibodies for leptospirosis reduced to 2%

Large increase in protein intake

Better farmer perceptions - preventive actions

Prevention of sanitary risks linked to rodents at rural/peri-urban interface - RATZOOMAN

A three-year research project with 1.45 million euros from the European Commission involving health and agricultural experts from eight countries

www.nri.org/ratzooman

RATZOOMAN Objectives

Identify and describe Yersinia, Leptospira and Toxoplasma species prevalence

Investigate the ecological and epidemiological determinants of rodent-borne zoonosis

Formulate sustainable participatory strategies for major stakeholders to bring about awareness of risk of disease, disease prediction and disease management

The End