Page 113 - Medical Parasitology_ A Textbook ( PDFDrive )

106 10 Nematodes: Roundworms

Loa loa
Fly Stages 1 Fly (genus Chrysops) Human Stages
takes a blood meal
(L3 larvae enter bite wound)

8 Migrate to head
and fly’s proboscis

2 Adults in subcutaneous
i tissue
7 L3 larvae

Adults produce
6 L1 larvae 3 sheathed microfilariae
that are found in
spinal fluid, urine,
4 Fly takes a sputum, peripheral
5 Microfilariae shed blood meal blood and in the lungs
sheaths, penetrate (ingests microfilariae)
fly’s midgut, and d
migrate to thoracic
muscles

i = Infective Stage
d = Diagnostic Stage
Fig. 10.17 Life cycle of Loa loa (Reproduced from https://www.cdc.gov/dpdx/loiasis/index.
html)

1. Microscopic examination
Detection of microfilariae stained with Giemsa in peripheral blood at
daytime.
2. Biopsy
Isolation of the adult worm from the eye or from a subcutaneous biopsy
specimen.
Treatment
DEC (8–10 mg/kg orally in 3 divided doses daily for 21 days) is effective against
both the adult and the microfilarial forms of L. loa. Severe adverse reactions may
develop following the sudden death of large numbers of microfilariae after giving
DEC. Administration of corticosteroids at the same time minimizes such reaction.
Surgical removal of the migrating adult worms that are found in the conjunctiva
or under the skin.
Prevention and Control
1. Avoiding areas where Chrysops are found
2. Avoid vector bites by using insect repellents and protective clothings
3. Treatment of positive cases