Mitigating Infectious Disease - Opportunities and Awareness for Permaculture Designers

MITIGATING INFECTIOUS DISEASEOPPORTUNITIES AND AWARENESS FOR PERMACULTURE DESIGNERS

Susan V. Cousineau, MSc. BITsusan.cousineau@gmail.com

OVERVIEW

Disease Overview: What & WhyDefinitions and Pathogen Types

Thinking FrameworksHow can we use good design to mitigate risks and impacts?

Illustrative Examples

Conclusions & Wrap-Up

Conclusions&

Wrap-Up

ThinkingFrameworks

IllustrativeExamples

Pathogen Types

ROADMAP

DiseaseOverview:

What & Why

Conclusions&

Wrap-Up

ThinkingFrameworks

IllustrativeExamples

Pathogen Types

Pathogen Types

ROADMAP

DiseaseOverview:

What & Why

WHAT ARE WE TALKING ABOUT?

Infectious diseases that spread between human and animalsRelationships between agriculture, poverty and disease, and our capacity to help at a grassroots level

We won’t be covering…crop diseases (per se)non-infectious diseases

DEFINITIONSinfectious disease: a disease that spread between hosts via a pathogen

pathogen ( = parasite): an organism that causes illnesse.g. bacterium, virus, fungi, protozoan, helminth worm

host: an organism that becomes infected by a pathogen; may or not show illness

e.g. insects, rodents, birds, humans

vector: an organism that transmits a pathogen between hostsoften invertebrates, including ticks, mosquitoes, flies, and snails

WHY ARE WE TALKING ABOUT THIS?

>1400 infectious diseases that affect humans, more emerging

We are in the third major disease era known to humankind

Between 1995 and 2008, global economic impact >$120 billion USD

KEY DRIVERS

Socio-economics

Environmental change

Nutrition

Water management

INFLUENCERISK MAGNITUDE

WHO 2013

CURRENT GLOBAL OUTLOOK

Many known diseases expanding their ranges; new ones emerging

Novel populations and driving factorsintensified farming; elderly and immunosuppressed; marginalized and extremely poor; global travelenvironmental degradation, habitat encroachment

Divestment in public health infrastructurepolitical unrest, economic disparity and declining social conditions

Conclusions&

Wrap-Up

ThinkingFrameworks

IllustrativeExamples

DiseaseOverview:

What & Why

Pathogen Types

Pathogen Types

Water-borne

Vector-borne

Vertebrate Hosts

Bacteria Protozoa

Water

Hosts(Humans, Livestock,Wildlife)

Vectors

Animals

Viruses Helminths

WATER-BORNE PATHOGENS

Transmitted through water via

aquatic vegetationcontaminated soilsinadequate sanitation

Many are bacterial infectionsEscherichia coliShigella spp.

and protozoans… SchistosomaFasciola trypanosomesGiardiaCryptosporidia

VECTOR DISEASES>17% of all infectious diseases

>1 million deaths/year

Flying insects: mosquitoes (malaria, dengue, yellow fever), sandflies (leishmaniasis) and blackflies (river blindness)

Ticks (Lyme disease, encephalitises, tularaemia), snails and triatomine bugs (Chagas disease)

“ANIMAL” DISEASES

Pathogens associated with a vertebrate, non-human host

Lyme diseaseHantavirus (e.g. Sin Nombre)

Diseases of wildlife-livestock interface

Rinderpest, blue tongue, foot-and-mouth

Diseases of farmed livestockAvian influenzaFasciolosis (liver flukes)

WATER-BORNE VECTOR-BORNE VERTEBRATE

SOCIOECONOMICS

• Housing• Sanitation• Storage

• Access to treatment

• Vector control

• Housing• Control (e.g.

fencing)

NUTRITION • Sanitation• Immunity

• Sanitation• Immunity

• Biodiversity loss

• Habitat change

ENVIRONMENT • Exposure to new pathogens

• Available vector habitat

• New pathogens• Livestock and

wildlife• Water accessWATER

MANAGEMENT

• Water sanitation

• Exposure

Conclusions&

Wrap-Up

IllustrativeExamples

DiseaseOverview:

What & Why

Pathogen Types

ThinkingFrameworks

Sanitation

ThinkingFrameworks

Health & Nutrition

Prevention

Holistic Management

8 Forms/RegenerativeEnterprise

Permaculture&

SystemsDesign

RegenerativeAgriculture

LearningModels

CulturalDialogue

This work is licensed under the Creative Commons Attribution-Noncommercial-No Derivative Works 2.5 Australia License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/2.5/au/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA. The ‘design principles’ have been adapted from David Holmgren’s book ‘Permaculture: Principles & Pathways Beyond Sustainability’. Permaculture Principles Poster 2.0

Ask relevant questions, gather information

Focus on health building

nutrition, soil, diversity

Design for minimum intervention

Close waste loops

DESIGN STRATEGIES

Zones, Sector and Element Analyses

Stacking functions, patterns and scales

Scales of permanence

Appropriate technology

Local resources and knowledge

CULTURAL

FINANCIAL

PERSONAL

SOCIAL ECOLOGICAL

EXPERIENTIAL

INTELLECTUAL

MATERIAL

WWW.8FORMS.ORG

Regrarians Platform

1. Climate 2. Geography 3. Water 4. Access 5. Forestry 6. Buildings 7. Fences 8. Soils 9. Economy 10. Energy

INFLUENCERISK MAGNITUDE

RISK MANAGEMENT

idiosyncratic risky events affect individual farms or firms e.g. infections of individuals; illness of the owner or labourers; single-farm outbreaks

covariate risky events affect many locations simultaneously e.g. major droughts, floods; fluctuating temperatures; epidemics either community level (meso) or entire region (macro) arise from war, natural disasters, price instability, financial crises

difficult to manage locally require a coordinated response

HOME GARDENSDRIP IRRIGATION

SANITATION

AGROFORESTRYEARTHWORKS

COMMUNITY TRAININGHOUSING & INFRASTRUCTURE

POLICY CHANGEMUNICIPAL GOVERNANCE

Frameworks for addressing social, economic, ecological needs

Pre-determined collaborative interdisciplinary “toolbox” approach

May require further integration with public health and organizational capacity

Seek to build knowledge, awareness and conduct thorough assessments

PERMACULTURE

PERMACULTURE

Frameworks for addressing social, economic, ecological needs

Pre-determined collaborative interdisciplinary “toolbox” approach

May require further integration with public health and organizational capacity

Seek to build knowledge, awareness and conduct thorough assessments

Conclusions&

Wrap-Up

ThinkingFrameworks

DiseaseOverview:

What & Why

Pathogen Types

IllustrativeExamples

WATER-BORNE VECTOR-BORNE VERTEBRATE

SOCIOECONOMICS

• Housing• Sanitation• Storage

• Access to treatment

• Vector control

• Housing• Control (e.g.

fencing)

NUTRITION • Sanitation• Immunity

• Sanitation• Immunity

• Biodiversity loss

• Habitat change

ENVIRONMENT • Exposure to new pathogens

• Available vector habitat

• New pathogens• Livestock and

wildlife• Water accessWATER

MANAGEMENT

• Water sanitation

• Exposure

WATER-BORNE VECTOR-BORNE VERTEBRATE

SOCIOECONOMICS Nicaraguan immigrants in

Costa RicaChagas Disease &

Palm Oil

Swine & Avian Influenzas

NUTRITION Old & New World Hantaviruses

ENVIRONMENT

SchistosomiasisMosquito

Diseases (Malaria & Dengue)

Nipah Virus in Malaysia

WATER MANAGEMENT

Fasciolosis in Livestock

NICARAGUANS IN COSTA RICA

Lind, J. (2009). The political ecology of intestinal parasites among Nicaraguan immigrants in Monteverde, Costa Rica.

Nicaraguan immigrants in Costa Rica suffer from . . .

higher intestinal parasitespoor housing infrastructurelack of access to health care

INTESTINAL PARASITES & NUTRITION

IPs result in chronic undernutritionstunting from poor nutrition and persistent infectionslong-term effects on growth, earning potential, immunity and cognition

people need more calories to grow and maintain activityinfected conditions amplify and reinforce poverty

micronutrient insufficiency: especially Vitamin A, zinc, iron, iodine~1 billion people suffer from insufficient food overall (“hunger”)far more from micronutrient deficiencies (often overlooked)

~15% of the global population; 1 billion considered “food insecure” (2009)

POLITICAL ECOLOGY OF DISEASE

political change; public health policy

industrialization, marginalization of communities

forced or voluntary immigration

HOUSEHOLD ECOLOGY

general sources of infection insufficient counter spacewashing and toilet facilities (dirty, absent, inadequate)storage (food, wastes, water)insufficient protection (rodents, mosquitoes, other insects)

cockroaches and flies carrying intestinal parasites

common sources of co-infection by Giardia, Toxoplasma gondii, Entamoeba histolytica, roundworms and hookworms

NICARAGUANS IN COSTA RICA

intestinal parasite prevalence higher in Nicaraguan immigrants than Costa Rican residents

protozoan infections (~15%) >> helminth worms (2%)prevailing medical treatments for helminths; routine rather than specific to cases

elders in communities familiar with plant and home remedies

younger members accustomed to taking pills from health care centres (e.g. Albendazole, Sentel)

Crowding = more parasites

Unsanitary kitchens = more vectors

Nicaraguans 8.7x more likely to have inadequate bathroom facilities than Costa Ricans

REMEDIES & SOLUTIONS

18 home remedies identified by both Costa Ricans and Nicaraguans

Apazote: Dysphania ambrosioidesGarlicGuara/o (“Costa Rican vodka”)Padra, yerba buena, coconut milk

kitchen, bathroom infrastructuregreywater systemsadequate access to health care, home ownership

SCHISTOSOMIASIS (“BILHARZIA”)

• Water-borne flatworms (Schistosoma) transmitted by freshwater snails

• Causes liver and intestinal damage

• Associated with overfishing, flood irrigation and ponds/dams

• Eggs are shed in faeces; enter waterways

SCHISTOSOMIASIS (“BILHARZIA”)

• Trematodes develop in freshwater Bulinus snails• free-swimming larval stage (“cercariae”) are

infectious to humans through skin contact

• ~200 million people infected worldwide; risks affect ~780 million

• Greatly increased with overfishing• use of fine-mesh seines• re-introduction in Kenya, Cameroon ineffective

IRRIGATION

A potentially major infectious disease risk

creates vector habitatdirect transmission of water-borne diseases

Flood irrigation an important source of emerging zoonoses

repeating contact between humans, wildlife and livestock

Better optionsdripline irrigationearthworks catchment and soil storage

CHEMICAL UV BIOSAND FILTERS BOILING

+ ineffective for protozoans

+ effective for all organisms

+ effective for most organisms

+ effective for most organisms

+ scaleable+ requires minimal training

+ community-scale

+ no training required

+ resistant to re-infection + non-toxic + appropriate

technology

- chlorine and chloramines

toxic

- technologically

expensive

- take 2-4+ weeks to “ripen”

- inefficient, energy

intensive- reliant on

ongoing inputs- limited access

for rural- dependent on proper building

- can be reinfected

- requires pre-filtration

- temperature and use sensitive

WATER SANITATION

BIOSAND WATER FILTERS

SOLUTIONScurrent treatment: Praziquantel

broad-spectrum anti-helminth given annually or as neededWHO’s list of most needed world medicines

improve sanitationplaying in and use of contaminated waterprovide clean drinking, washing water

reduce snail populationspredatory fish (multiple species)native African river prawn

CHAGAS DISEASE & PALM OIL

African oil palms planted throughout South America for biodiesel

habitat for bug vectors of Chagas disease (Trypanosoma cruzi)

Primarily agricultural workers affected

~150 million people at risk~18 million infected

PALM OIL PLANTATIONS & BIOFUELS

Extensive planting of African oil palm (Elaeis guineensis) for oil and biodiesel production throughout South America

habitat for triatomine bugs; estimated ~65% infection in some areas

Brazil’s Ministry of Agriculture estimates area of palm cultivation could expand from 60 000 ha today to >6 million by 2025

Political/socioeconomic goal to decrease dependency on coca

increased exposure of working poor (13% of the population)

CHAGAS DISEASEbugs pierce the skin, then defecate

parasite contained in faecesitching breaks the skin for infection

long-term cardiac damagedeath occurs 10-30 years later

found in crevices of dwellingsthatch roofs, behind furniture, in animal shelters, cracks, wood piles

>150 species, 24 families of animals carry the parasite, making re-infestation frequent

SOLUTIONSPyrethroid pesticides

bugs are often resistant

Eliminating packrat middensanecdotal, but seems to be effective

Sealing cracks, walls, entries

Opportunity for design and site hygiene that reduces hiding locations

NIPAH VIRUS

loss of forest habitats, agricultural expansion

changes in size, location and structure of bat colonies

bats forage in fruit trees around urban and residential areas

spread to humans, livestock

NIPAH VIRUS MALAYSIA

Swine infected through feeding on dropped fruit contaminated with bat droppings and urine

A result of environmental encroachment, possibly climate changes, and food-animal production into wildlife habitat

Outbreaks in 1997-1998 spread from fruit bats to domestic pigsdisease and mortality in livestock and agricultural workers1999: high human mortality created widespread panic and had catastrophic effects on the Malaysian swine industry

WILDLIFE & LIVESTOCK

Major contribution of zoonotic disease (~75%)

Livestock and pets have disease risks for wildlife

Even if not symptomatic, can act as reservoirs and “amplifiers”

Increasingly important with environmental and social changes

PIGS, BIRDS & INFLUENZAS

Intensive pig and poultry systems increasing

short turn-around compared to ruminantsfewer workers per animal, but more infections

Pigs are “viral mixing grounds”highly varied, omnivorous diet creates pathogen opportunitiesknown infections from wild birds and domestic poultry

Intensified conditions create disease “playgrounds”crowding, low genetic diversity, unsanitary conditions

INDIRECT TRANSMISSION

INDIRECT TRANSMISSION

CONSUMPTION/INFECTION

SOLUTIONSPrevention is the best cure

separate wildlife and livestockfencing, guardian dogs most effective

Avoid free-range foraging by livestock, e.g. where fruit bats occur

Keep animal husbandry standards highHealth, nutrition, space, shelter

Build and maintain good soil healthfiltration of viruses, other pathogens shed in wasteroots and soil structure sequester pathogens deep in soil stratamicrobial and macrofaunal diversity consume pathogens

MOSQUITO-VECTORED DISEASESMajor mosquito-borne diseases of the tropics and subtropics

Malaria: Plasmodium spp. protozoans; Anopheles mosquitoesDengue (“breakbone fever”): dengue virus; Aedes aegypti mosquitoes

Climate change impactsincreasing range, reproduction

Deforestation, land use change clearing creates sunlit pools

Malaria in 2015: 440k dead, 214 million sickDengue: 100 to 400 million cases: 500k hospitalized, ~25k deaths (mostly children)

ENVIRONMENTAL CHANGE & DISEASE RISKS

Climatic effects on water- and vector-borne diseaseslengthen transmission season; speed reproductiontends to increase geographic range (altitude, latitude)

Natural disasters affect sanitation, exposure, socioeconomics

Habitat change and degradationloss of biodiversityhomogenizationdense vegetation; stagnant secondary forest undergrowth

CLIMATE CHANGE

In the US: costs $2-4 billion/year in direct public health costs

Between 2030 and 2050, will cause ~250k additional deaths/yearmalaria, diarrhea, malnutrition

Key impacts for mosquito-vectored diseasesincreasingly variable rainfall patternsmore frequent and severe flooding and droughtincreasing minimum temperatures

CHOLERA

Bangladesh: outbreaks predicted by sea surface temperature and heightchlorophyll levels (phytoplankton/algal blooms)

DEFORESTATION

Creates mosquito-friendly habitatalso for other insect vectors (sandflies, ticks)

Creates mosaics of fragmented habitat support diversity and abundance of vectors, but few predatorsmore human-adapted species

Road construction increases access, exposure

Plus - muddy, rutted tracks fill with rain

Community-led trainings for prevention of dengue

Developed by Sustainable Sciences Institute

founded by Eva Harris, UC Berkeley

Basically the only method shown to be effective

DENGUECurrent strategy: spraying with larvicides, pesticides

organophosphate temephos for day-to-daymunicipalities spray malathion during outbreaks, but ineffectiveresistance common

BiocontrolsWolbachia bacteriaMesocyclops copepods

Bed nets ineffective (day feeders)

MALARIA

Current treatmentsinsectide-impregnated bed netsintermittent treatment for pregnant womenindoor spraying

Potential biological control agentse.g. fungi, nematodes: parasitize and kill larval mosquitoesinefficient for control; not widely usedmosquito fish largely been ineffective except in a few cases

For mosquito-vectored diseases, reducing habitat is key

spraying ineffective at bestmany mosquito (and other insect) species resistant

Community-led training most effective so faremptying, cleaning, covering containerslocally developed trainingreduced pesticide use

ThinkingFrameworks

DiseaseOverview:

What & Why

Pathogen Types

IllustrativeExamples

Conclusions&

Wrap-Up

FINDING SOLUTIONS. . .

Global agreementSolutions must be interdisciplinary, collaborative, holistic, etc.

Proven success with community-led solutions

Accounting for multiple factorshabitat and biodiversity lossclimate changewildlife presencesanitation needsetc.

– World Health Organization, 2013, xii

“A much broader-based response to the evolving patterns of infectious disease risk is needed — one that entails integrative strategies and that is environmentally sustainable, socio-ecologically sensitive and adaptive to changing conditions. [This will require] stronger and

harmonized strategic alliances between all organizations, sectors and institutions concerned with development, environment and social justice,

including public health.”

FINDING SOLUTIONS. . .

Global agreementSolutions must be interdisciplinary, collaborative, holistic, etc.

Do we wait for organizations to cooperate, or begin at a grassroots level?

Institutional bickering, territoriality and domain specialization endemicCoordination of funding, political regime change, international trade…

Sanitation

ThinkingFrameworks

Health & Nutrition

Prevention

Holistic Management

8 Forms/RegenerativeEnterprise

Permaculture&

SystemsDesign

RegenerativeAgriculture

LearningModels

CulturalDialogue

APPROACHES WITH BROAD APPLICATIONS

Each problem has multiple solutionsEach solution may be able to address multiple problemsDesign from patterns to details; follow the 12 principlesGather information, relevant knowledge, and community support

APPROACHES WITH BROAD APPLICATIONS

Preventionreduce or eliminate vector habitatencourage biodiversity in contiguous land areasreduce contact between wildlife and livestock

Sanitationprioritize multi-step processes for creating clean water (e.g. BSFs)close waste loops (composting, vermicompost)build soil health and vegetation to absorb waste

Health & Nutritionintricately linked to poverty through immunity, earning potential, cognition, physical capacity: rebuild nutrient-dense food and habitatssocioeconomics begins with household ecology, prevention & sanitation

REFERENCES

• Cascio, A., Bosilkovski, M., Rodriguez-Morales, a. J., & Pappas, G. (2011). The socio-ecology of zoonotic infections. Clinical Microbiology and Infection, 17, 336–342. http://doi.org/10.1111/j.1469-0691.2010.03451.x

• Jones, B. A., Grace, D., Kock, R., Alonso, S., Rushton, J., Said, M. Y., … Pfeiffer, D. U. (2013). Zoonosis emergence linked to agricultural intensification and environmental change. Proceedings of the National Academy of Sciences, 110(21), 8399–8404. http://doi.org/10.1073/pnas.1208059110

• Lambin, E. F., Tran, A., Vanwambeke, S. O., Linard, C., & Soti, V. (2010). Pathogenic landscapes: interactions between land, people, disease vectors, and their animal hosts. International Journal of Health Geographics, 9(1), 54. http://doi.org/10.1186/1476-072X-9-54

• Mawdsley, J. L., Bardgett, R. D., Merry, R. J., Pain, B. F., & Theodorou, M. K. (1995). Pathogens in livestock waste, their potential for movement through soil and environmental pollution. Applied Soil Ecology, 2(1), 1–15. http://doi.org/10.1016/0929-1393(94)00039-A

• Pongsiri, M. J., Roman, J. O. E., Ezenwa, V. O., Goldberg, T. L., Koren, H. S., Newbold, S. C., … Salkeld, D. J. (2009). Biodiversity Loss Affects Global Disease Ecology. BioScience, 59(11), 945–954. http://doi.org/10.1525/bio.2009.59.11.6

• Genevieve V. Weaver, Joseph Domenech, Alex R. Thiermann, and W. B. K. (2013). Wildlife Disease Association - FOOT AND MOUTH DISEASE A LOOK FROM THE WILD SIDE, 49(4), 759–785. http://doi.org/http://dx.doi.org/10.7589/2012-11-276

• Wilcox, B. A., & Colwell, R. R. (2005). Emerging and Reemerging Infectious Diseases : Biocomplexity as an Interdisciplinary Paradigm, 244–257. http://doi.org/10.1007/s10393-005-8961-3

• World Health Organization. (2013). Research priorities for the environment, agriculture and infectious diseases of poverty. World Health Organization technical report series.

HELPFUL RESOURCES

DIARRHEAL DISEASES

Symptom of other diseases usually caused by bacteria (e.g. cholera, shigellosis, typhoid) may also be caused by viruses or protozoa (e.g. amoeba, cryptosporidium and giardia)

Amoebic dysentery is the most commonaffects ~500 million people each year

Diarrhea overall the most common cause of illness and mortalitykills 1.8 million out of ~4 billion cases of illness annually

CRYPTOSPORIDIUM

• 7 species, one (c. parvum) focused as cause of clinical zoonotic disease in humans, livestock and other mammals (Robertson and Smith 1992); implicated in a large proportion of diarrhoeal outbreaks in pigs, sheep and cattle (Reynolds et al., 1986; Angus, 1990; Robert et al., 1991; Villacorta et al., 1991). In cattle and sheep cryptosporidiosis and the associated diarrhoea is almost exclusive to young animals and thus peaks of disease outbreaks occur around lambing and calving times (Fig. 2). Infection with Cryptosporidium often occurs in conjunction with other enteropathogens such as rota- virus, enteropathogenic E.coli and Salmonella spp., and such multiple infections increase both morbidity and mortality rates (Angus, 1990); animals ingest transmissive cysts that are excreted in large numbers in infected animals (Smith 1992); as few as 10 can result in disease; severity governed by immunological status of host (Ungar 1990); can be deadly in severely immunocompromised, esp. HIV, patients (Current 1987) due to excessive watery diarrhoea and dehydration; otherwise, 7-14 days of acute infection (nausea, anorexia, vomiting, abdominal pain, fever, diarrhoea) with general malaise and cramps up to a month; start 5-10 days after oocyst ingestion; excretion of oocysts can continue long after disease symptoms have ceased (Ungar 1990); water course contamination potentially a problem because oocysts are not removed by current water treatment practices (resistent to standard chlorine levels, West 1991); sand-bed filtration currently only effective method of removal (Smith 1992)

GIARDIA

• binucleate flagellates; three species on basis of host range and morphology; focused on G. lamblia (or G. intestinalis or G. duodenalis); causes disease in mammals, birds and reptiles; only two stage life-cycle: infective cyst and vegetative trophozoite; after cyst ingestation, excystation occurs in small intestine and two trophozoites are released; divide binary fission in small intestine and cause symptoms of giardiasis; some encyst, are shed in faeces and cycle continues; waterborne transmission via the infective cyst is major factor in spread; one of the most common waterborne epidemic diarrhoea in US (Deng and Cliver 1992); severity of disease varies greatly from asymptomatic to chronic diarrhoea. In addition to diar- rhoea, common symptoms which may persist for up to 6 weeks include abdominal cramps, nausea, loss of appetite, malaise and weight loss; sand filtration effective as for Cryptosporidium (Rose et al 1989)

SHIGELLA

• Four species: Shigella sonnei (the most common species in the United States) S. flexneri, S. boydii; S. dysenteriae Type 1 causes deadly epidemics; symptoms start 1-2 days post infection, with diarrhea (often bloody); tenesmus (feeling like having to make a bowel movement but is empty; fever; abdominal pain; typically last 5-7 days, although bowel activity may take several weeks to return to normal. Normally resistant to re-infection by the same species, but susceptible to others. Can be treated with antibiotics, but often resistant: usually left untreated will subside; keep well hydrated. Avoid drugs that slow the digestive system, e.g. Imodium

• long-term complications include arthritis (~2%), blood stream infections, seizures and hemolytic-ureic syndrome

RISK FACTORS: WATER-BORNE DISEASES

poor sanitation (household infrastructure: up next)

infected livestock around water

infected vegetation, e.g. manure applications

CHAGAS DISEASE (“KISSING BUG DISEASE”)• serious health problem in many parts of South and Central America; wide

distribution of host species; In the natural cycle, triatomine bugs commonly occur in native palms found in the Amazon and elsewhere in northern South America. Several studies have reported high rates of Chagas infection in these insects, sometimes exceeding 65% (WHO 2013 379).

• - mainly transmitted by faecal contamination of skin or conjunctivae that have been broken by the bite of many Reduviid bugs, especially Triatoma and Rhodnius spp.

• - originated in forest environments but have adapted well to domestic ones; some effective control of T. infestans in Brazil, Chile and Uruguay, but still present

• - difficult to eradicate due to re-infestation from forest habitat; >150 species from 24 families of sylvatic and domestic animals infected with etiological agent, Trypanosoma cruzi

• - ~25% of the 600 million in Latin America, specifically the poor (13% of total population) are at risk

• - most countries of Central America, and Colombia, Venezuela, species is Rhodnius prolixus; and in Gran Chaco region (Argentina, Bolivia, SW Brazil, Paraguay), T. infestans: re-infestations likely due in part to resistance to pyrethroid insecticides

• - Associated with biofuel plantations in Brazil

RISK FACTORS: VECTOR-BORNE DISEASES

standing water, dense vegetation (larval habitat)

monoculture plantations

lack of control methods, e.g. mosquito nets

FASCIOLOSIS

• two species of parasitic flatworms (trematodes) that mainly affect the liver• Fasciola hepatica and F. gigantica• are leaf-shaped worms; visible to the naked eye; can hybridize

• until recently, human cases occurred occasionally • increasingly reported from Europe, the Americas and Oceania (F.

hepatica only) and from Africa and Asia (both species)

• ~2.4 million people are infected in more than 70 countries worldwide, with several million at risk

• infection rates 80-100% in some countries

• large economic losses to sheep and cattle industries• e.g. £23 million in the UK

HANTAVIRUS PULMONARY/RENAL SYNDROME

• Hantaviruses found in Asia, Europe and Americas; all rodent hosts• North America: deer mouse + Sin Nombre virus (~35-50% mortality)• Central America: rice rat + Choclo virus• Europe: bank voles + Puumula virus (0.5% mortality)

• Transmitted through biting and scratching• humans infected through aerosolized faeces or urine

• Climatic events and human activities that reduce biodiversity associated with outbreaks

RISK FACTORS: VERTEBRATE DISEASES

loss of biodiversity; increases in host species

climatic variability

infected livestock; poor husbandry