World Society for the Protection of Animals Zoonotic Diseases and Natural Disasters Professor Stan Fenwick Veterinary Public Health Murdoch University/WSPA

World Society for the Protection of Animals

Zoonotic Diseases and Natural Disasters

Professor Stan Fenwick

Veterinary Public Health

Murdoch University/WSPA


WHO – “during floods, reports and rumours are common about problems created by animals such as dogs, rats, mice and snakes”


Zoonoses associated with floods

• Leptospirosis• Anthrax• Rabies• Salmonellosis


• Zoonoses are infections which are naturally transmitted between vertebrate animals and people

• People, animals, insects and the inanimate environment are all involved in cycles of zoonotic infection


An appreciation of the zoonoses and attempts to control them requires a sound knowledge of

the epidemiology of the diseases and the behaviour of both people and animals which

may facilitate interspecies transmission


Zoonoses can be classified as follows

Type of infectious agent(e.g. bacteria, virus, parasite)

Type of reservoir hostMode of transmission


Transmission of zoonotic infections may be direct, indirect via arthropod vectors, or

from environmental foci

Direct zoonosisCyclozoonosisMetazoonosisSaprozoonosis


Direct Zoonosis

An infection which can be directly or mechanically transmitted to people from animals, and which is capable of being

maintained in a single species of animal

Most of the important zoonoses that can occur following flooding are direct zoonoseseg. leptospirosis, anthrax, rabies


• Direct anthropozoonosis (or via fomites)• Host-adapted serovars, maintenance hosts act as

carrier animals, inapparent infections• Herbivores long shedding, carnivores short • Severe infections in secondary hosts (humans and

animals)• Over 200 serovars, all capable of infecting any

animal• Moist environmental conditions favour survival

outside hosts, endemic zones

Leptospirosis

World Society for the Protection of AnimalsMaintenance hosts

L. Hardjo

- cattle

L. pomona L. tarrasovi

- pigs

Many serovars, e.g.

L. australis, L. zanoni, L. copenhageni

– rodents (rats/mice)


Occupational hazard in rice-growing communities – 200 deaths in Thailand and 6000 sick in 2000, cattle, pigs and

rodents thought to be reservoirs, transmission via urine contaminating paddy

fields.


Occupational risks


Recreational risks

Sabah, Malaysia, 2000, Eco-challenge race – 50 out of 80 athletes contracted leptospirosis.


Other risks!!!!


• Contact with infected urine or contaminated water• Common occupational disease via intact mucous

membranes, aerosols or skin abrasions • Anicteric disease is common form seen in Australia,

vague symptoms, flu-like, fever, headache, myalgia• Icteric disease more severe, uncommon in Australia,

this form commonly seen with rodent-associated serovars, jaundice, haemolytic crisis, can cause death

• Person-person transmission rare, dead-end hosts

Transmission and Human Disease


Symptom (n=179) %

Headache (123) 68.7%

Myalgia (109) 60.9%

Severe Fever (102) 57.0%

Sweats (101) 56.4%

Chills (95) 53.1%

Arthralgia (89) 49.7%

Nausea (70) 39.1%

Vomiting (62) 34.6%

Back Pain (50) 27.9%

Mild Fever (49) 27.4%

Respiratory Symptoms 20.1%

Conjunctival Suffusion 13.4%

Renal Involvement (22) 12.3%

Vision Disturbance (17) 9.5%

Rash (15) 8.4%

Diarrhoea (14) 7.8%

Pulmonary Haemorrhage 5.6%

Liver Involvement (4) 2.2%

Symptoms of human leptospirosis


Leptospirosis and floods

• 2002Thailand 50 cases, multiple serovars• 2006Brazil 193 cases, L.

copenhageni• 2008Guyana 68 cases (6 deaths), ?

serovars• 2009Fiji 8 cases (3 deaths), ?

serovars


• Bacillus anthracis, Gm +ve spore-forming rod• Worldwide, Russia, Asia, Africa, S.America• ‘Hot spots’ in warm humid areas where natural

cycles exist• All mammals susceptible but pigs, dogs, cats

relatively resistant• Birds can disseminate spores, chickens

resistant, some birds susceptible• Spores have a long survival time in the

environment

ANTHRAX


• Animal by products, wool, hides, bone meal, meat, all involved in spore transmission

• Cutaneous infections most common, inhalation, intestinal in rural areas, person to person rare

• 1-7d incubation, spores germinate, bacteraemia, papules, vesicles, oedema (black), fatal septicaemia (toxins)

• Agricultural workers, rural people, vets, travellers etc.

ANTHRAXTransmission and Human

Disease


Cutaneous anthrax

Anthrax pneumonia


Indonesia 2007 – several human deaths associated with eating meat from cattle that had died of anthrax (annual occurrence)Australia 2007 – cutaneous anthrax in a worker processing a dead cow for meat and bone meal

Vietnam 2008 – 15 people died or became sick through eating a dead cow


Anthrax and floods

• No specific disease incidence data following floods

• Floods remove and deposit soil and can expose anthrax spores in endemic areas

• Seasonal flooding of rivers in southern africa has led to outbreaks of anthrax in cattle and wildlife

• Animals that have died as a result of disease or accident are eaten in some cultures, may pose a risk if anthrax cases occur


• Family Rhabdovirus, genus Lyssavirus• Direct zoonosis• Worldwide in all continents – few countries free, e.g. NZ• Some countries free by eradication e.g. UK

While this disease is not directly associated with flooding, in SE Asia the potential congregation of large

numbers of animals in relief camps and temporary shelters could result in the inclusion of rabid animals,

particularly in India where rabies is widespread

RABIES


1. Classical rabies2. Lagos bat virus3. Mokola virus4. Duvenhage virus5. European bat virus6. European bat virus7. Pteropus (Australian)

lyssavirus

Genotypes of Lyssavirus


Distribution

New Zealand

Japan

UK

World wide, EXCEPT


Worldwide 30-50,000 deaths per year result from classical rabies

It is estimated that a person dies from this infection every 15 minutes!

Lancet 2002


• Dogs most important domestic hosts, other domestic animals can also be involved e.g. cats, cattle

• Many wild reservoirs which differ between regions; principally canids (foxes, wolves, jackals) but also mongooses, skunks, raccoons, bats

• Haematophagous, insectivorous and frugivorous bats all can transmit rabies and related viruses

RABIES Epidemiolo

gy


• Animals differ in susceptibility, dogs show intermediate susceptibility, humans, cats and cattle highly susceptible, pigs resistant

• Highest incidence in Asia, in particular India • Endemically stable, few new reports of infections

extending in countries except raccoons in E. USA and Bat Lyssa Virus in Northern Europe

RABIES Epidemiolo

gy


• Transmission to people mainly by bites via virus in saliva

• Aerosol, transplacental and transmammary transmission in bats, found in bat saliva in zoos

• Oral transmission in highly susceptible species (eg. foxes), not documented in people

RABIESTransmissio

n


• Incubation 4d - 6y recorded, depending on where bitten

• Clinical rabies invariably fatal• Prodromal period (behavioural changes)• Excitative period (hydrophobia, aerophobia in

people); 1 dog in India bit 40 people/9 dogs in 4h• Paralytic period (may be predominant phase with

some virus types - dumb rabies) – dangerous as may be easily misdiagnosed at this stage in animals

RABIESDisease

manifestations


Now considered the 10th most common infectious cause of

deaths in the world

India - 30,000 deaths annually

Pakistan - 2-5000 deaths per year

Thailand – 2-300 deaths per year


Rabies and floods

• As for anthrax little specific information is available • However, post-flooding, large numbers of uncontrolled

dogs may congregate near relief camps• This concentration of dogs will facilitate rabies

transmission in the event of a rabid animal being present in the group

• After Hurricane Katrina public health officials warned of a possible increase in rabies cases as flood waters disrupted domestic and wild animals from their natural habitats


In a disaster area where rabies is endemic, assume

that all dogs could potentially be rabid, and in particular keep well away from free roaming, aggressive dogs.

Feed, describe, locate and leave!


Cyclozoonosis

Infections which require at least two vertebrate hosts, one of which may be human, to complete their life cycle

These include many of the parasitic zoonoses which are not usually associated with flooding, although handling dogs in a hydatid endemic region could result in infection

e.g. Taenia solium, Echinococcus granulosus


Metazoonosis

Diseases of vertebrate animals which can affect man, the infectious agents of which replicate, develop in, and are transmitted by, an invertebrate vector

This group includes all the arthropod-borne infections, which should be considered following flooding due to a concurrent increase in vector

populationse.g. Mosquito and tick/mite -borne infections

(Dengue, Japanese encephalitis, rickettsial infections)


Diseases of vertebrate animals which can affect people, the infectious agents of which are either capable of replicating in inanimate sites, or require an inanimate environment for the development of an infectious stage of their life cycle eg. Histoplasmosis, Toxocara canis, enteric bacteria

Salmonella can survive in contaminated water or soil for several months, assisting transmission between animals and from animals to people and is therefore

a potential cause of animal and human infections following flooding

Saprozoonosis


Salmonella

• Over 200 serovars, both host-adapted (S. typhi) and non-host adapted (S. typhimurium, S. enteritidis)

• Domestic and wild animal reservoirs, most infections asymptomatic

• Domestic animals show increased shedding and clinical disease following periods of intense stress e.g post flooding/congregation in relief camps

• Human infections via food, water or direct contact


Non-Zoonoses

• Bacterial infections• Viral infections• Parasitic diseases• Diseases associated with

nutrition


Bacterial infections of animals

• Clostridial infections• Tetanus• Botulism• Blackleg• Enterotoxaemia

• Haemhorragic septicaemia (pasteurellosis)

• Secondary infections post-trauma• Respiratory• Skin• Mastitis


Viral infections of animals

The majority of transboundary animal diseases are viral in origin, and, while not specifically associated with flooding, it is important to be aware of their potential to spread in stressed, contained animal populations, and to cause subsequent problems for affected rural populations


• Rinderpest• FMD• Rift Valley Fever• Bovine spongiform encephalopathy (BSE)• Contagious bovine pleuropneumonia (CBPP)• Classical swine fever (CSF)• African swine fever• Highly pathogenic avian influenza (HPAI)• Peste de petits ruminants (PPR)• Newcastle disease

MAJOR TRANSBOUNDARY ANIMAL DISEASES

(blue indicates that diseases are recognised in Asia)


• Compromised food security• Major production losses for animal products• Loss of valuable livestock genetics• Increase in costs of production• Disruption to local and international trade• Inhibition of investment in livestock sector• Public health and environmental issues• Animal welfare concerns

CONSEQUENCES OF TRANSBOUNDARY ANIMAL DISEASES


Parasitic infections

• Moist conditions following flooding favour survival of worm eggs

• Post flooding, the congregation of animals in relief camps or other areas will facilitate parasite transmission

• In addition, stressed animals will be more prone to the effects of parasites

• Nematode and trematode infections most likely• Ectoparasite infections will also increase – may result

in tick-borne infections e.g. Babesiosis, theileriosis, flystrike


Diseases associated with nutrition

• Flood-damaged feeds• Mycotoxicoses• Toxic plants eaten due to lack of feed• Inanition due to unusual feedstuffs• Starvation• Problems resulting from contaminated

water


Occupational disease risks post-flooding

• Leptospirosis is the disease most commonly associated with floods due to the contamination of water with animal urine, in particular rodent urine

• Mosquito-borne diseases will also be a potential risk, e.g. dengue, Japanese encephalitis, malaria

• If large numbers of stray dogs are congregated on dry ground, then dog bites and potentially rabies are risks

• Infected wounds, tetanus, respiratory infections • Food and waterborne diseases – Cholera, typhoid and

other enteric infections from contaminated water and food


EpidemiologyRisk factors for diseases following

floods• Overcrowding• Nutritional changes• Contaminated water supplies• Wounds and injuries• Inclement weather• Vectors• Other stressors


Diagnosis of diseases in the field

• Minimal facilities• Temporary laboratory facilities• Access to permanent laboratory facilities


Minimal facilities

• Microscope, simple stains, McMaster slides, salt solutions, sample collection equipment

• Pen-side tests as developed (lepto dip stick – humans only; anthrax rapid tests – humans only)

• Anthrax is probably the only bacterial infection that simple laboratory facilities could diagnose, i.e. use of McFadyean’s polychrome methylene blue stain to identify the bacteria in blood smears

• Parasite diagnosis, worms, worm eggs• Blood-borne parasites (Babesia, Theileria, Trypanosoma)


Temporary laboratory facilities

• Possible incubator, allowing simple bacteriology, although usefulness doubtful, ? Salmonella

• Refrigerator/freezer to allow storage of samples for retrospective diagnosis

• Serum sample storage; work with human agencies

• Simple test kits, e.g. rapid ELISA


Control of Diseases following flooding

• General principles of disease control• Examples of disease control for

diseases potentially associated with flooding


Definition of Prevention

“Actions aimed at eradicating, eliminating, or minimizing the impact of disease and disability. The concept of prevention is best defined in the context of levels,

traditionally called primary, secondary, and tertiary prevention”


Definition of Control

“The reduction of disease incidence, prevalence, morbidity or mortality to a locally acceptable level as a result of

deliberate efforts; continued intervention measures are required to maintain the

reduction”


Emergency Preparedness“an animal or human disease

emergency can have serious socio-economic consequences, which may

affect a countries whole national economy”


“The only thing more difficult than planning for an emergency is having to explain why you didn’t!”


General Control Strategies for ZoonosesMeasures may need to be implemented on

individual/herd, local/community, national and international levels

1.Individual/herd: chemoprophylaxis, arthropod control and avoidance, hygiene, vaccination, clean water, safe food, disinfection of fomites, avoidance of close contact

2.Local/community: arthropod and rodent control, education, mass chemotherapy, eradication of animals, restriction of animal movement, vaccination, pasteurisation, isolation of patients, infection control

3.National/International: quarantine, restriction of imports, movement control for animals, international notifications and networks, international response teams


Integration of medicine and

veterinary medicine in approaches to

control

“And most importantly”

(“ONE MEDICINE - ONE HEALTH”)


Some examples of control from the

zoonoses

“it is vital to understand the epidemiology of a disease to

be able to control it”


• Vaccination of cattle, pigs, deer, dogs• Need virulent, local serovars in vaccines, little cross-

immunity, killed, annual revaccination• Protective clothing• Avoid contact with animal urine/contaminated water• Control of wild reservoirs e.g. rodents• DD - influenza, meningitis, hepatitis, dengue, scrub

typhus• Doxycycline prophylaxis for humans

Leptospirosis control


Vaccination for specific diseases

• Anthrax –animals, human vaccine used in US• HS and clostridial vaccines used in ruminants• Avian influenza and ND vaccines for poultry• FMD, PPR, CSF – vaccines available for animals• Rabies - vaccine available for animals and humans• Japanese encephalitis – human vaccine available• Typhoid and cholera – human vaccines available


Occupational safety

• Staff, VERU teams, volunteers, owners

• Hygiene, hand-washing facilities

• Protective clothing – boots, gloves, glasses, masks

• Prophylactic drugs – malaria, antibiotics

• Vaccination

• Record keeping and incident reporting


BIOSECURITY

An understanding of the principles of biosecurity is vital

for individuals working in Disaster Management, in

particular when developing and managing temporary shelters or

relief areas, and in assisting communities to prevent

disease.


Biosecurity is ….

• A series of Management Practices that are employed to reduce the chance of importing infectious diseases into a country, a region, a village or a relief camp

• These practices can also help to slow the spread of infectious diseases if disease incursions occur


• Following a natural disaster factors are present that potentially increase the spread and prevalence of infectious diseases in animal populations. Many of the diseases are of food safety or economic concern

• Stressed animals are more prone to infectious diseases

• A vibrant agricultural community is an important resource in producing and maintaining a healthy environment and assisting affected populations to recover from disasters

Biosecurity is important for a number of reasons


In order to effectively begin to develop a biosecurity program it is important to review

the risk areas that may be present

•Risk assessment helps to determine the areas or factors that are most likely to lead to the spread of infectious agents

•Risk management is the second step. Here a preventive plan is developed and implemented.

•Risk communication is the final step. In this step, all members of the management team, farmers, suppliers and service personnel are informed of the plan to ensure cooperation and buy-in.


Roles and responsibilities

• Development of a biosecurity plan for relief camps or the disaster area is initially the responsibility of the veterinarian in charge of the DM team in consultation with the VERU team leader and senior government staff

• Once protocols have been established, they should be enforced as far as possible by the DM/VERU team members and government staff


Livestock Herd or relief camp

Wildlife

Other animalsNeighbor’s Animals

Visitors & Suppliers

*Purchased Products (Feed, etc )

*Purchased animals


Biosecurity usually involves screening and testing incoming animals, quarantine or isolation for newly purchased or returning animals, and finally a monitoring or surveillance system to detect disease incursions.

Some of these activities may be difficult to integrate into a disaster

response plan, however it is important to be aware of the

principles of biosecurity


To protect animal health


To protectfood supplies and human health


And to prevent the spread of disease causing hardship for affected

communities


One way to concisely introduce Biosecurity and Biocontainment is to use

the acronym IRS

IRS stands for

Isolation-Resistance-Sanitation


World Animal Health Information

Database (WAHID ) Interface • Before biosecurity protocols can be developed it is

important to know the diseases endemic in the country, this information is not always available

• Government vets in the team can supply information• WAHID is a very useful source of global information http://www.oie.int/wahis/public.php?page=home• The WAHID Interface provides access to all data held

within OIE's new World Animal Health Information System (WAHIS ). It replaces and significantly extends the former web interface named Handistatus II System


OIE international health standards

Terrestrial Animal Health Code Manual of Diagnostic Tests and Vaccines for Terrestrial Ani

mals

• The Health Codes detail measures to be used to prevent the transfer of infectious agents pathogenic for animals and humans

• While principally for use in international animal movements these codes are a very useful source of information to assist the development of biosecurity plans


In summary

• Biosecurity relies on:• Controlled access• Protective equipment• Disinfection• Closed herds• Isolation on introduction


Bio-security is not difficult ….it’s just inconvenient!

Documents

World Society for the Protection of Animals Zoonotic Diseases and Natural Disasters Professor Stan Fenwick Veterinary Public Health Murdoch University/WSPA