Related Diseases/Symptoms

Mode of Transmission

Cause(s) of Emergence


Fever, headache, sore throat, nausea

Contact with urine or feces of infected rodents

Urbanization/conditions favoring infestation by rodents


Fever, conjunctivitis, cough, red blotchy rash

Airborne; direct contact with respiratory secretions of infected persons

Deterioration of public health infrastructure supporting immunization

Norwalk and Norwalk-like agents

Gastroenteritis; epidemic diarrhea

Most likely fecal-oral; alleged vehicles of transmission include drinking and swimming water, and uncooked foods

Increased recognition


Acute viral encephalomyelitis

Bite of a rabid animal

Introduction of infected reservoir host to new areas

Rift Valley

Febrile illness

Bite of an infective mosquito

Importation of infected mosquitoes and/or animals; development (dams, irrigation)

Ross River

Arthritis, rash

Bite of an infective mosquito

Movement of infected mosquitoes or people


Enteritis; diarrhea, vomiting, dehydration, and low-grade fever

Primarily fecal-oral; fecal-respiratory transmission can also occur

Increased recognition

Venezuelan equine encephalitis


Bite of an infective mosquito

Movement of mosquitoes and amplification hosts (horses)

Yellow fever

Fever, headache, muscle pain, nausea, vomiting

Bite of an infective (Aedes aegypti) mosquito

Lack of effective mosquito control and widespread vaccination; urbanization in tropics; increased air travel

TABLE 2-1 Part 3: Examples of Emergent Protozoans, Helminths, and Fungi


Related Diseases/Symptoms

Mode of Transmission

Cause(s) of Emergence


Anisakiasis: abdominal pain, vomiting

Ingestion of larvae-infected fish (undercooked)

Changes in dietary habits (eating of raw fish)

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