Viruses

Arboviruses
Equine encephalitides, Colorado tick fever, yellow fever
Equine encephalitides
1. Mode of transmission, Culex species
2. Reservoir probably birds, small rodents and reptile and amphibian
3. Incubation period: 5-15 days
4. Symptoms – affects brain, spinal cord and meninges; high fever, stupor, spasiticity,tremors
Colorado tick fever
1. Mode of transmission: Dermacentor andersoni
2. Reservoir – small mammals
3. Incubation period: 4-5 days
4. Symptoms: acute fever, remission and recurrence lasting 2-3 days
Yellow fever
1. Mode of transmission: Aedes aegypti
2. Reservoir: man, Aedes aegypti, monkeys
3. Incubation period: 3-6 days
4. Symptoms: sudden fever onset, headache, nausea, vomiting, jaundice
Infectious hepatitis
a. Mode of transmission through contact, water, milk and food
b. Reservoir is man
c. Incubation period: 15-50 days, commonly 25
d. Symptoms: fever, nausea, abdominal pain, jaundice, necrosis of liver
Poliomyelitis
a. Mode of transmission: oral contact, milk
b. Reservoir is man
c. Incubation period: 7-12 days; ranging to 3-21
d. Symptoms: fever, headache, gastrointestinal disturbance, stiffness of neck and back
with or without paralysis
Rabies
a. Mode of transmission: bite of rabid animal; airborne spread from bats to man in caves
with many bats
b. Reservoir: small carnivores including bats
c. Incubation period: 4-6 weeks
d. Symptoms, almost always fatal form of encephalitis; headache, fever, paralysis