Page 72 - JSOM Fall 2024

An Ongoing Series

Sandfly Fever

Jason Jarvis, MSc

ABSTRACT
Biting sandflies are known for transmitting leishmaniasis, but there is no vaccine to counter the sandfly virus, vaccines go a
sandflies also transmit sandfly fever viruses that may disrupt long way to protect against the acquisition of certain arthropod-
military operations. Sandfly fever is caused by serotypes of the borne diseases such as yellow fever, Japanese encephalitis, and
Phlebovirus genus (primarily the Naples, Sicilian, or Toscana dengue.
serotypes). The illness is known colloquially as “three-day fe-
ver” and “papataci fever.” The clinical course of the disease Phlebotomus and Lutzomyia genus sandflies encompass
normally spans about 3 days, with patients exhibiting a pro- roughly 1,000 species (and subspecies) and exist across the
dromal phase consisting of fatigue, chills, abdominal pain, tropical and subtropical zones, except for Australia. Their
and possibly facial flushing and tachycardia. Disease onset is greatest impact as disease vectors occurs within the following
marked by hyperpyrexia, myalgia, and arthralgia. The incu- regions and countries: the Mediterranean, the Middle East,
bation period is typically 3–5 days, with viremia in humans northern India, Pakistan, Afghanistan, China, Central Amer-
lasting typically less than 1 week. This manuscript describes ica, and South America. 4
sandfly appearance, behavior, and geographic distribution. It
then lists comparable diseases for differential diagnosis. Fi- Phlebotomus (Old World) genus sandflies in subtropical zones
nally, as no vaccine exists for the sandfly virus, it concludes are much more active during the summer compared with those
with steps for preparation and prevention to prevent out- in the tropics, which are active throughout the year. 4
breaks from disrupting military operations.
Sandflies are less than 5mm in length and can pass through
Keywords: pappataci fever; sandfly fever; phlebovirus; infec- mosquito netting and typical window screens. Owing to their
tious diseases; arbovirus diminutive size, however, the proboscis of the biting female is
unable to penetrate clothing. This limitation of the sandfly pro-
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boscis does not impede the insect from feeding on other warm-
blooded animals, as will be discussed further in this article.
Introduction
Biting sandflies are primarily known for their role in the trans- Sandflies resemble mosquitoes, though the body of the sand-
mission of leishmaniasis. Besides infecting humans and other fly is covered in small hairs, and the head of the sandfly is
animals with the leishmania protozoa, sandflies can transmit set closer to the body than that of the mosquito. In addition,
bartonellosis (Bartonella bacilliformis), Chandipura virus, while mosquito wings are held close to the body when at rest,
Changuinola virus, vesicular stomatitis viruses, and sandfly sandfly wings are held above the body at roughly a 45° angle
fever viruses. The sandfly fever viruses exist within the phle- while at rest.
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bovirus genus taxonomic grouping and are geographically
bound to their sandfly vectors. Phlebotomus genus sandflies As the sandfly is an inefficient flyer, its flight pattern consists
inhabit the Old World (Europe, Africa, and Asia) and vector of a series of “hops” along the ground, gaining a meter or so
Sicilian, Naples, Karimabad, and Salehabad species viruses. in altitude before landing. Most species are exophagic (feeding
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Lutzomyia genus sandflies inhabit the New World (the Amer- outdoors) and seek blood meals at night. In the daytime, sand-
icas) and vector Chagres, Punta Toro, Candiru, and Alenquer flies rest on or within natural objects such as animal burrows,
viruses. 3 termite mounds, and ground detritus. Eggs are not laid in wa-
ter but require a humid environment in which to incubate;
passage of the sandfly fever virus occurs both transovarially
Background and Clinical Presentation
(mother-to-egg) and transstadially (egg-larva-pupa-adult). Lut -
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As with any arthropod-borne disease, knowledge of and avoid- zomyia (New World) genus sandflies are most prevalent within
ance of the arthropod vector is a key preventive strategy. While forested areas. 5
*Correspondence to jjarvis18d@gmail.com . .
SSG Jason Jarvis is a teaching faculty member at the College of Remote and Offshore Medicine, Birzebbuga, Malta, and a PhD student in Health
Professions Education program at Widener University, Chester, PA.

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