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Document 0037
DOCN M94A0037
TI Experiments on the possible role of leeches as vectors of animal and
human pathogens: a light and electron microscopy study.
DT 9412
AU Nehili M; Ilk C; Mehlhorn H; Ruhnau K; Dick W; Njayou M; Department of
Zoology and Parasitology, Ruhr-University Bochum,; Germany.
SO Parasitol Res. 1994;80(4):277-90. Unique Identifier : AIDSLINE
MED/94352942
AB The presence and survival of pathogens inside the gut of leeches were
studied by means of light and electron microscopy. In African leeches
from Cameroon, blood was serologically positive for human
immunodeficiency virus (HIV) and hepatitis B; blood of Hirudo
medicinalis bought in German pharmacies contained up to 11 different
species of bacteria. In experiments done at low (3 degrees C) and high
(22 degrees, 32 degrees C) temperatures, it was shown that ingested red
and white blood cells survive for long periods. The time was prolonged
to at least 6 months in cases in which the leeches were stored at 3
degrees C. The same effect occurred with pathogens. Bacteriophages
(viruses of bacteria) and bacteria persisted in large numbers for at
least 6 months in the gut of experimentally infected leeches. Protozoan
parasites such as Toxoplasma gondii, Trypanosoma brucei brucei, or
Plasmodium berghei were even capable of reproducing inside the gut of
the leech. In the case of Plasmodium parasites, this proceeded at low (3
degrees C) and high (22 degrees C) temperatures until all erythrocytes
were used up. These parasites survived as long as the erythrocytes and
lymphocytes were of good shape, i.e., around 5-6 weeks p.i. Single
stages survived longer, especially at low temperatures. However,
electron microscopy studies gave no hint of penetration of such
pathogens into the unicellular salivary glands, which would initiate a
direct transmission. Such transmission, however, is possible--many fish
leeches directly transmit several blood parasites--when the leeches are
squeezed during skin attachment or when they are manipulated by dropping
salt solution on their backs while they are sucking. Consequently, the
leech is a potential vector of many pathogens, especially in regions
with an endemic spread of human and/or animal pathogens.
DE Animal Bacteriophage T4 *Disease Vectors Escherichia coli Human
Leeches/MICROBIOLOGY/*PARASITOLOGY Mice/PARASITOLOGY Microscopy
Microscopy, Electron Plasmodium berghei Toxoplasma Trypanosoma brucei
brucei JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).