The diseases in which animals act as reservoir hosts and humans

become accidentally infected, e.g. hydatidosis, visceral larvae migrans. 

 These diseases are normally present in humans but could be transmitted to animals, e.g. amoebosis 

• About 71,8 % of new diseases emerge from wild life population
 Organism must have ability to cross species barrier and opportunity to do so by either spill over events (incidental human outbreaks without sustained human‐human transmission) or

specie jump (pathogen evolution to efficiently transmit amongst human hosts) • Bats are reservoirs for 61 high‐impact viral zoonosis:

 Nipah virus, Hendra virus, Ebola, SARS

• Rodents are a similar comparison group (68 viral zoonosis)
 Lassa fever, Argentine, Bolivian, Venezuelan, Brazilian haemorrhagic fevers 

Emerging disease ‘hot spots’ are regions where diseases are more likely to originate.
Usually regions that have high population density and/or are ill‐equipped to cope. Global effort for EID surveillance and investigation should be allocated to high risk zones before large‐scale emergence. 

•   Clean food and water; avoid dung and urine get into drinking bowls or hay racks

•   Remove faeces from animal enclosures frequently

•   Make sure that the air is well ventilated.

•   Do not keep animals overcrowded.

•   Vaccinate animals against important diseases

•   Bury or burn the dead animals. Always investigate when an animal dies suddenly.

•   Keep animals in clean, dry places. Move enclosures and stables regularly and keep them clean

•   Quarantine newly purchased animals

•   Strict biosecurity 

Orthomyxoviridae: influenza viruses: A, B, C 

Hemagglutinin (H) and neuraminidase (N) proteins: H5N1 

Highly mutagenic virus; antigenic drift produce small genetic 

changes to evade the immune system

By antigenic shift a new subtype (can produce pandemics)

• Epidemiology

• In animals: last incident in 2008 due to HPAI H7N7

• No fatalities observed in the UK, H5N1 pandemic in 2009

Cystic Echinococcosis (hydatic disease): infection with the larval stage of Echinococcus granulosus

• Definitive host‐ dogs; Intermediate hosts: sheep, cattle, goats, humans

• Alveolar Echinococcosis: infection with the larval stage of Echinococcus multilocularis

• Definitive hosts: dogs, foxes, coyotes; intermediate hosts: rodents, humans

Transmission to humans

:consumption of viable eggs from infected animal faeces, 

hand‐to‐mouth

contaminated food or water, fomites

Transmission to animals:

Intermediate: ingestion of eggs from the environment

Final : eating affected parts of intermediate host 

 Cystic echinococcosis - granulosus - cyst have stronger capsule• Animals:

•Causative agent: Burkholderia mallei •Middle‐East, South America, India

•Transmission- highly transmissable
•Reservoir is infected Equidae
• to humans via discharges from infected horses •Entry via skin abrasions, mucous membranes •Aerosols
•Vets, horse‐workers, butchers at particular risk, water troughs

• Parasite (Nematode) Trichinella spiralis

• Transmission:

• Associatedwithpigs(alsowildpigs),humanandhorses.Rats,wildcarnivoresasreservoirs. • consumptionofraw/undercookedmeat
• 1975‐2005:39confirmedcasesintheUKbyconsumptionofproductsabroadorimported

• Symptoms: variable
• Musclepain,fever,swellingofeyelids.
• Mostcommonsites:diaphragm,ribs,tongueandjaw

• Hygienic measures including isolation and removal of sick individuals • Inspection of meat sample (wild and uncontrolled housing conditions • Cold treatment (freezing) of meat

• Caused by spirochete Borrelia burgdorferi • Epidemiology:

Endemic in south of England, Lake District, Scottish Highlands and Islands

1,163 human cases reported in the UK in 2012

Very common zoonose in northern hemisphere

and wet climates

• Transmission:

Reservoir: rodents, dogs might be reservoirs too

Bite of tick Ixodes ricinus

prefer to feed on deer

• Life cycle of the tick and Borrelia spp. are

  closely linked‐ transmission is seasonal

  At least 24 h tick attachment for transmission 

  
  

   

  Disease in animals:

  • Dogs, horses, cattle rabbits

    unspecific symptoms: fever, lethargy, lameness,

    anorexia. Disease in humans:

    erythema migrans (red expanding skin reaction). Flu like symptoms with fever, malaise, headache

    days to weeks: widespread EM lesions, neurological: meningitis, cranial nerve damage and facial paralysis

    Chronic: arthritis 

    
    

    
    

     

    • Diagnosis:
    • Difficult: not always erythema migrans, tick missing

    • Treatment:
    • antibiotics

    • Prevention:

    • Prevent tick attachment to large mammals and humans

    • Controlling undergrowth around footpaths

    • Inspect and treat livestock for ticks

    • Control access of rodents to farmed deer

    • Permethrin‐treated cotton balls to decrease tick population on rodents

    • Personal protection: adequate clothing, prompt removal of ticks, avoid humid area with abundant vegetation. 

Etiology: Hookworms( Ancylostoma brazilense, Ancylostoma caninum) Epidemiology: Worldwide but more frequent in warmer climates Transmission: direct penetration of skin by larvae

Clinical signs:
relate to migration of larvae through skin: itching, pain, local inflammation; usually heals spontaneously
Children at greater risk

• Prevention: regular de‐worming, don’t walk barefoot, removal of faeces