       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).

