Top 30 Zoonotic Diseases Part 5

What are the three clinical syndromes in humans caused by larva migrans?

Cutaneous, visceral, and ocular.

What is the classic case syndrome associated with rabies in domestic mammals?

Furious form characterized by restlessness, unprovoked attacks, and incoordination.

Which virus is responsible for rabies?

Rabies virus, a neurotropic virus in the genus Lyssavirus, family Rhabdoviridae.

What is the primary vector for Rocky Mountain spotted fever (RMSF) in the United States?

Dermacentor andersoni, also known as the Rocky Mountain wood tick.

What are the common symptoms of influenza in humans?

Fever, lethargy, coughing, nasal discharge, nausea, vomiting, diarrhea, and myalgia.

What are the clinical signs of listeriosis in ruminants?

Encephalitis leading to circling, facial nerve paralysis, and abortion in the last trimester.

With which animals is highly pathogenic avian influenza (HPAI) often associated?

Birds, particularly those exhibiting symptoms such as coughing and sneezing.

What is the major public health precaution to prevent larva migrans infection?

Avoid contact of skin with larvae or ingestion of eggs or larvae.

Which zoonotic disease can result in severe neurologic symptoms and is transmitted by infected ticks?

Rocky Mountain spotted fever (RMSF).

How does Listeria monocytogenes typically enter human populations?

Through ingestion of contaminated food or exposure to infected animals.

What is the route of transmission for the influenza A virus among animals?

Fecal-oral route, fomites, and aerosols.

What is a notable characteristic of Listeria in terms of its survivability?

Listeria can grow at normal refrigerator temperatures (40°F or 4.4°C).

CS of larva migrans in animals?

Usually gastroenteritis

What are the syndromes associated with larva migrans in humans?

Cutaneous, visceral and ocular syndrome

What is the cause and CS of cutaneous larva migrans?

Cause are Ancylostoma spp. and strongyloides spp.

1. Vermiform rash

2. Intense pruritus

3. ± pain

Cause and CS of visceral larvae migrans?

Toxocara spp. Bayliascaris procyonis and Ascaris suum.

CS:

1. Depends on the organ affected

2. Myocarditis

3. Hepatitis

4. Meningoencephalitis

5. Usually in young children (1-4yr)

Cause and CS of ocular larva migrans?

Toxocara and B. procyonis

1. Visual impairment

2. Ocular pain

3. ± Strabismus

4. Usually in children 7-8yr

Which larvae can infect human?

1. Ancylostoma spp (hookworms)

2. Strongyloides spp. (threadworms, cause larva current similar to cutaneous larva migrans)

3. Toxocara (dog roundworm)

4. Ascaris suum (swine worm)

Precautions to not get infected with worm larvae?

Avoid contact of skin w/ larvae (to prevent cutaneous form) or ingestion of eggs or larvae (to prevent viscelar or ocular form)

Forms of rabies in domestic mammals?

Furious and dumb form

CS of furious rabies?

1. Restlessness

2. Unprovoked attacks

3. Incoordination

4. Pica

5. Abnormal bellowing in cows

CS of dumb rabies?

1. Hypersalivation due to inability to swallow

2. Dropped jaw

3. Progressive limb paralysis

4. Coma

5. Death

Rabies CS in wild mammals?

1. Lose fear of humans

2. Nocturnal animals are wandering around during daylight

Rabies CS in humans?

1. Malaise

2. Fever

3. Headache

4. Pruritus at bite site

5. Abnormal behavior

6. Sensitivity to light and sound

7. Delirium

8. Difficulty swallowing

9. Pharyngeal spasms

Cause of rabies?

The rabies virus, a neurotropic virus in the genus Lyssavirus, family Rhabdoviridae.

How are humans infected with rabies?

Contact with infectious saliva or neurologic tissues through MM or blocken skin (usually due to bite) or infected organ transplants

Precautions to prevent rabies infection?

1. Avoid bites from inf. animals

2. PPE

3. Seek medical care for prophylaxis if exposed

4. Humans at risk of exposure (vets) should be vaccinated and have titers checked every 2 yrs.

RMSF CS in dogs?

1. Fever

2. Anorexia

3. Mucopurulent oculonasal discharge

4. GI signs

5. Joint or muscle pain

6. ± NS

RMSF in humans?

1. Fever

2. Rash

3. Headache

4. Myalgia

5. Multiorgan involvement

RMSF cause and hosts?

Caused by Rickettsia rickettsii, a pleomorphic obligate IC G- cocobacillus. Rodents may be amplifying host.

How is RMSF transmitted?

Spread by bite of an infected tick:

1. D. andersoni - RM wood tick present in most of NA

2. D. variabilis - American dog tick, mosr of MA

3. R. sanguineus - brown dog tick, AZ and Mexico

Precautions: use biosecurity lvl 3 to culture, not directly transmitted between humans and animals

Influenza CS in birds?

1. Coughing

2. Sneezing

3. Diarrhea

4. Hemorrhage

5. NS

Influenza CS in pigs?

1. Coughing, sneezing

2. Fever

3. Conjunctivitis

4. Oculonasal discharge

Influenza CS in humans?

1. Fever, lethargy

2. Coughing, nasal discharge

3. Nausea, vomiting, diarrhea

4. Myalgia

Etiology of influenza?

Caused by influenza A virus, an orthomyxovirus. Its usually host adapted, but can occasionally infect additional species.

What determines influenza A viral subtype?

1. Hemagglutinating Ag (H)

2. Neuramidase Ag (N)

How are humans infected with influenza?

By contact with hosts like birds, pigs and ferrets, via aerosol and fomites.

Its spread among animals via fecal oral route, fomites and aerosol.

Precautions: annual influenza vaccination and PPE when handling animals

Important swing influenza virus?

H1N1, transmission to humans is regular.

What influenza virus can infect humans?

H3N2 or H2N8, but it isnt a cause of diz in humans

Listeriosis CS in ruminants?

1. Encephalitis - brainstem lesions affecting cranial nerves which leads to circling, nystagmus, facial nerve paralysis, ptyalism

2. Abortion - usually last trimester without premonitory signs

Listeriosis CS in humans?

1. Usually acute febrile gastroenteritis

2. Pregnant women: flu like illness that may lead to abortion or neonatal sepsis

Listeriosis etiology?

L. monocytogenes, a G+, non spore forming coccobacillus. It lives in the plant-soil environment and animals GI tracts worldwide.

How are animals and humans infected with listeriosis?

Animals by ingesting or inhalation, can enter small wounds in the buccal mucosa.

Humans:

1. Ingestion of cont. food

2. Exposure to inf. animals (typically those that have aborted, not those with encephalitis)

Precautions: PPE when handling inf. animals, particularly if they aborted.

Problem in uncooked food because it can grow in normal fridge temp. of 40F or 4C