What diseases are endemic to the US Virgin Islands?

Endemic Diseases in the US Virgin Islands

The US Virgin Islands have several endemic diseases, with the most significant being dengue fever, chikungunya, and Zika virus, all transmitted by Aedes mosquitoes that breed in household water storage systems like cisterns. 1, 2, 3, 4

Vector-Borne Diseases

Mosquito-Borne Viral Diseases

1. Dengue Fever

   • Transmitted by day-biting Aedes mosquitoes, particularly Aedes aegypti
   • Clinical presentation: fever, headache, myalgia, arthralgia, and rash
   • Incubation period: 4-8 days (range: 3-14 days)
   • Can progress to dengue hemorrhagic fever in severe cases
   • Management: supportive care, avoid aspirin, monitor platelet counts and hematocrit 1

2. Chikungunya

   • First reported outbreak in the US Virgin Islands occurred in 2014-2015
   • Transmitted by Aedes mosquitoes
   • Incubation period: 2-3 days (range: 1-12 days)
   • Clinical presentation: fever, severe joint pain (often chronic), headache, myalgia
   • Higher incidence observed among women and individuals aged 55-64 years
   • Management: supportive care, no specific treatment available 1, 5, 4

3. Zika Virus

   • Major outbreak occurred in the US Virgin Islands from January 2016 to January 2018
   • 1,031 confirmed cases (967 Zika disease, 64 Zika infection)
   • Transmitted by Aedes aegypti mosquitoes
   • Associated with microcephaly in newborns and Guillain-Barré syndrome
   • Clinical presentation: mild fever, rash, conjunctivitis, muscle and joint pain
   • Management: supportive care 1, 2

Rickettsial Infections

• African Tick Bite Fever (Rickettsia africae)
  • Endemic in the eastern Caribbean
  • Transmitted by cattle ticks
  • Clinical presentation: fever, headache, myalgia, eschar at bite site, regional lymphadenopathy
  • Treatment: doxycycline is the first-line therapy 1

Environmental Factors Contributing to Disease Transmission

1. Cisterns and Water Storage Systems

   • 45.7% of household cisterns in the US Virgin Islands contain mosquitoes
   • Aedes aegypti found in 27.4% of cisterns, accounting for 83.3% of total mosquitoes identified
   • Significant breeding sites for disease vectors 3

2. Climate Factors

   • Increased temperature associated with higher case counts of Zika virus
   • Tropical climate supports year-round mosquito breeding 2

Prevention Strategies

1. Vector Control

   • Use of insecticide-treated bed nets
   • Application of insect repellents containing DEET
   • Wearing protective clothing
   • Proper maintenance of water storage systems
   • Elimination of standing water 1

2. Traveler Precautions

   • Travelers to the US Virgin Islands should take preventive measures against mosquito bites
   • Consider appropriate prophylaxis if indicated
   • Be aware of symptoms and seek prompt medical attention if they develop 6

Diagnostic Approach for Returning Travelers

For travelers returning from the US Virgin Islands with fever:

1. Initial Assessment

   • Obtain detailed travel history, including specific islands visited, activities, and duration
   • Document onset of symptoms relative to travel dates
   • Assess for specific symptoms: fever pattern, joint pain, rash, headache, myalgia

2. Laboratory Testing

   • Complete blood count (look for thrombocytopenia, common in dengue)
   • Dengue PCR (if within 1-8 days of symptom onset)
   • Serology for dengue, chikungunya, and Zika
   • Consider thick and thin blood smears to rule out malaria if clinically indicated 1, 6

Reporting Requirements

All cases of dengue, chikungunya, Zika virus, and other notifiable diseases diagnosed in travelers returning from the US Virgin Islands should be reported to local health departments as per CDC guidelines 1.

The US Virgin Islands is a territory where vector-borne diseases pose a significant public health challenge, primarily due to the presence of Aedes mosquitoes and suitable breeding conditions in water storage systems. Awareness of these endemic diseases is crucial for both residents and healthcare providers to implement appropriate preventive measures and ensure prompt diagnosis and treatment.