Upload
tamara-price
View
46
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Impact of rodents. 4 nights’ catch, 1917 Lascelles, Victoria, Australia. Impact of rodents. Agriculture. Field damage/reduced yield of staple crops. Yield of vegetable crops, marketability. Loss, damage, contamination to stored crops. Health. Zoonosis – lassa fever, plague, leptospirosis. - PowerPoint PPT Presentation
Citation preview
Impact of rodents
4 nights’ catch, 1917 Lascelles, Victoria, Australia
Impact of rodents
AgricultureField damage/reduced yield of staple crops
Loss, damage, contamination to stored crops
Health
Zoonosis – lassa fever, plague, leptospirosis
Yield of vegetable crops, marketability
Contamination – dysentery (Salmonella etc.)
PropertyBuildings, furniture, utensils, roads, wires, clothes, blankets, fishing nets …..
>750 million poor in rice-producing Asia!>750 million poor in rice-producing Asia!70% of the 70% of the
world’s poor world’s poor live in Asialive in Asia
Nutrition from rice (selected Asian countries, 1999)Nutrition from rice (selected Asian countries, 1999)
Sources: FAO online database (2001); World Development Report (2002); World BankSources: FAO online database (2001); World Development Report (2002); World Bank
0
10
20
30
40
50
60
70
80
Mya
nmar
Laos
Vie
tnam
Ban
glad
esh
Cam
bodi
aIn
done
sia
Thai
land
Phi
lippi
nes
Kor
ea
Chi
na
Mal
aysi
a
Indi
a
Japa
n
Wor
ld
Calories
Protein
Region Region and and populationpopulation
Rice Rice produced produced (tonne)(tonne)
Loss to Loss to rodents rodents (%)(%)
Rice eaten Rice eaten (kg/year)(kg/year)
People fed People fed per year if no per year if no rat lossesrat losses
IndonesiaIndonesia
210 million210 million
50,000,00050,000,000 1717 249249 33 million33 million (52% calories)(52% calories)
VietnamVietnam
80 million80 million
31,000,00031,000,000 3030 280280 8 million8 million
(67% calories)(67% calories)
AsiaAsia
3.6 billion3.6 billion
540,000,000540,000,000 55 150150 180 million180 million
(32% calories)(32% calories)
1010 360 million360 million
Rice field losses to rats Rice field losses to rats
Losses to rats in Bangladesh Losses to rats in Bangladesh
Field losses 10 – 20 % (up to 100% in some years)
Storage losses 5 – 10 % (can be > 200kg per house)
Foregone production ?
Other crop losses
Field losses 10 – 20 % (up to 100% in some years)
Storage losses 5 – 10 % (can be > 200kg per house)
Foregone production ?
Other crop losses
Damage Damage crops, stored crops, stored grain, clothes, grain, clothes, houseshouses
Loss of Loss of production production increases increases crop areacrop area
EnvironmentalEnvironmentalrisks from risks from poisonspoisons
Disease Disease impactsimpacts
Rats are the No. 1 pest affecting rice Rats are the No. 1 pest affecting rice production in many Asian countriesproduction in many Asian countries
Rodents and DiseaseRodents are vectors and reservoirs for more than 60 different diseases.
Hantavirus
The Plague
Leptospirosis
Rat Typhus (rickettsia)
Neuro-angiostrongyliasis (rat lungworm)
are five of the major rodent-borne diseases that commonly affect human populations in Asia
Why rodents?
Why are rodents important reservoirs and vectors of human disease?
Mammals with common physiology
Commensality with long “co-evolution” living in close proximity to humans
Generalist feeders exploiting waste and human/livestock food
Rodents can pick up and transmit more than 60 different diseases
Morbidity rate of Morbidity rate of LeptospirosisLeptospirosis by province, by province, NortheasternNortheastern region, region, Thailand Thailand 1996 - 20021996 - 2002
0- 2.40- 2.4 2.41 -152.41 -15
1919
9696
19971997 1919
9898
19991999
15.01 - 5015.01 - 50 > 50> 50Morbidity rate/100,000Morbidity rate/100,000
200020002001200120022002
W. Tangkanakul W. Tangkanakul et al. et al. 2005. 2005. SE Asian J Trop Med Public HealthSE Asian J Trop Med Public Health 36, 36,
YearYear CasesCases IncidenceIncidence
(/100,000) (/100,000)
DeathsDeaths
19961996 398398
19971997 23312331 3.43.4
19991999 60806080 9.89.8 266266
20002000 1428514285 23.723.7 362362
20012001 1021710217 16.416.4 171171
20022002 68646864 9595
Leptospirosis human epidemiology in ThailandLeptospirosis human epidemiology in Thailand
7 to 9 times more males affected7 to 9 times more males affected
71-84% farmers; most 25-54 years71-84% farmers; most 25-54 years
Peak incidence in Aug to Nov (rains)Peak incidence in Aug to Nov (rains)
Serotypes: australis, sejroe, pyrogenesSerotypes: australis, sejroe, pyrogenes
Higher incidence if villages had pot Higher incidence if villages had pot
holes in roadsholes in roads
Information on leptospirosis in Asian Information on leptospirosis in Asian countries is extremely limited. countries is extremely limited.
Little is known about:Little is known about:The status of rodent diseases in Asia The status of rodent diseases in Asia
that affect humans and/or their livestockthat affect humans and/or their livestockWhich rodents are key reservoir speciesWhich rodents are key reservoir speciesThe persistence of the infective parts of The persistence of the infective parts of
the disease life cycle in rice agro-the disease life cycle in rice agro-ecosystemsecosystems
Leptospirosis human epidemiology in ThailandLeptospirosis human epidemiology in Thailand
Leptospirosis & Typhus in Lao PDRLeptospirosis & Typhus in Lao PDR
In 2001-2003 at Mahosot Hospital in In 2001-2003 at Mahosot Hospital in
Vientiane, of 427 adults with unexplained Vientiane, of 427 adults with unexplained
fever, from serological evidence:fever, from serological evidence:
10% leptospirosis 10% leptospirosis
10% murine typhus 10% murine typhus
15% scrub typhus 15% scrub typhus
Main risk factor – time spent in flooded paddies
Health impacts of rodent diseasesHealth impacts of rodent diseases
Epidemics of rodent-borne diseases can have a Epidemics of rodent-borne diseases can have a significant impact on a local rural economy. significant impact on a local rural economy.
Zoonosis can cause disability at key times and lead to no Zoonosis can cause disability at key times and lead to no crop, a late crop, or reduced crop yield. crop, a late crop, or reduced crop yield.
In poorer communities, disability for a month at a key time In poorer communities, disability for a month at a key time may lead to no crop, a late crop, or reduced crop yield. may lead to no crop, a late crop, or reduced crop yield.
Rodent diseases can lead to a debt treadmill! Rodent diseases can lead to a debt treadmill!
The Plague
Etiologic agent Yersinia pestis - bacillus
Bubonic Plague: enlarged, tender lymph nodes, fever, chills and prostration.
Septicemic Plague: fever, chills, prostration, abdominal pain, shock and bleeding into skin and other organs
Pneumonic Plague: fever, chills, cough and difficulty breathing; rapid shock and death if not treated early
Pharyngeal and Meningitic Plague also documented
Discovery of new foci = based on human cases!World Distribution of Plague, 1970-2005Discovery of new foci = based on human cases!World Distribution of Plague, 1970-2005World Distribution of Plague, 1970-2005Importance of Plague in modern timesImportance of Plague in modern times
Transmission
flea bites
meat consumption
airborne
long distance transport
(a)
(b)(c)
Stenseth, N.C, Aikimbayev, A., Atshabar, B.B., Begon, M., Belmain, S.R., Bertherat, B., Carniel, E.,
Gage, K.L., Leirs, H. and Rahalison, L. (in press) Plague: Past, Present and Future. PLoS Medicine.
Surat, Surat, Gujarat, Gujarat, India, 1994India, 1994
Squalid high-density slum conditions and poor sanitation promote transmissionSqualid high-density slum conditions and poor sanitation promote transmission
Confusion fuelled by poor levels of information in government press statementsConfusion fuelled by poor levels of information in government press statements
Media reports unconfirmed/suspected cases, exaggerating death tollsMedia reports unconfirmed/suspected cases, exaggerating death tolls
Agricultural exports and cargo embargoed, export loss of more than $420 millionAgricultural exports and cargo embargoed, export loss of more than $420 million
Investor confidence plummets, $600 million to $3 billion loss to Indian economyInvestor confidence plummets, $600 million to $3 billion loss to Indian economy
45,000 people cancelled flights to India45,000 people cancelled flights to India
International migrant workers strandedInternational migrant workers stranded
Divali [Festival of Lights] cancelledDivali [Festival of Lights] cancelled
Official death toll was 56Official death toll was 56
Approx. 700 suspected casesApprox. 700 suspected cases
Speculation that it was not plague Speculation that it was not plague continues to this daycontinues to this day
SuratSurat
Urban outbreaks of Urban outbreaks of plague will happen plague will happen againagain
Can we learn from Can we learn from the past?the past?
Economic non-Economic non-disease costs can disease costs can be very highbe very high