25 - 169 - MOSQUITO-BORNE VIRAL DISEASES

Question 1

Flavivirus that have demonstrated skin tropism with cutaneous manifestations

Answer 1

dengue virus (DENV)
West Nile virus (WNV)
Spondweni virus (SPOV)
Zika virus (ZIKV)
yellow fever virus (YFV)

Question 2

• In the first 24 to 48 hours of the febrile episode, erythematous flushing of the face, neck, and chest is common, likely caused by capillary dilation.
• By day 3 to 5 of illness, a generalized morbilliform dark erythematous eruption with areas of clearing described as **“islands of white in a sea of red” **is seen in 70% of patients presenting with rash

Answer 2

Dengue

Question 3

Unique to this virus is its ability to be transmitted from human to human through body fluids, sexual contact, and vertically from mother to fetus

Answer 3

Zika Virus

Question 4

ZIKV RNA persists in semen longer than in blood, saliva, or urine for up to how many months after the onset of illness?

Answer 4

6 months

Question 5

• Most infections in humans are asymptomatic (~80%).
• In 20% of infected patients, a mild febrile illness is associated with nonpurulent conjunctivitis, rash, malaise, and arthralgia, which will resolve within 2 to 7 days, and rarely requires hospitalization.

Answer 5

Zika virus infection

The classic ZIKV exanthema appears within 1 to 2 days of illness and is associated with low-grade fever in 55% of patients

Question 6

characterized by microcephaly, chorioretinitis, hearing loss, irritability, hypertonia, and esophageal dysfunction

Answer 6

ZIKV congenital syndrome

Question 7

Guillain-Barré syndrome (GBS) is associated with what mosquito-borne illness?

Answer 7

Zika virus infevtion

Question 8

hallmark of yellow fever virus infection

Answer 8

jaundice

Question 9

This infection has 2 phases:

1. The first “acute” phase usually causes fever, muscle pain with prominent backache, headache, shivers, loss of appetite, and nausea or vomiting.
   - Most patients improve after 3 to 4 days of illness.
2. In 15% of patients, a second “toxic” phase ensues within 24 hours of the initial remission with high fever, jaundice, abdominal pain, vomiting, mucosal bleeding, and GI hemorrhage.

Answer 9

Yellow fever infection

Question 10

A maculopapular rash appears in 5% to 22% of patients as a roseola-like, nonpruritic eruption, characterized by pink macules or papules, 5 to 10 mm in diameter, frequently affecting the torso and proximal extremities but sparing the palms and soles and lasting 5 to 7 days

Answer 10

West Nile Virus Infection

Question 11

common complication reported in 96% of West Nile Virus-infected patients for a median of 36 days

Answer 11

Fatigue

Question 12

• Fewer than 1% of patients develop neuroinvasive disease, classified as meningitis, encephalitis, or acute flaccid paralysis.
• Cranial nerve palsies are found in about 10% of patients and most commonly involve the second and seventh cranial nerves, causing optic neuritis (see later) or peripheral facial palsy, respectively.

Answer 12

West Nile Virus

Question 13

Approximately 70% of acute CHIKV infections are symptomatic, presenting with abrupt onset of high fever (>39°C), headache, severe polyarthralgia and myalgia, and an erythematous maculopapular rash

Answer 13

Chikungunya

• Most patients have joint pain and swelling with severe morning stiffness, consistent with in inflammatory arthritis
• joint pain is typically symmetrical, and almost any joint can be affected, especially during the acute phase, although the distal extremities are affected more frequently.

Question 14

most common and feared complication of Chikungunya

Answer 14

Chronic, episodic, often debilitating, polyarthralgia or polyarthritis associated with fatigue