Leishmania tropica

Leishmania tropica

<p align="CENTER"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: large;"><i><b>Leishmania tropica</b></i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: large;"><b> (Wright, 1903) Lühe, 1906</b></span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>ETYMOLOGY:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> Named for the tropics</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>SYNONYMS:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Helicosoma tropica</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> Wright, 1903; </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Herpetomonas tropica</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> Patton, 1912; </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Herpetomonas furunculosa</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> (Wright, 1903) Patton, 1922.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>HISTORY:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> The first person to describe the organism was Wright in 1903 who saw them in the cutaneous lesion of an Armenian patient undergoing treatment in Boston. The sandfly was shown to be the vector of this parasite by Sergent et al (1921). </span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>GEOGRAPHIC DISTRIBUTION:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> This organism is found in North Africa, Southern Europe, and the Middle East through India into western China. It is considered that this is mainly a human disease that on occasion also infects animals.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>LOCATION IN THE HOST:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> In the mammalian host, the only stage that is present is the amastigote that is found within histiocytes and macrophages in the skin.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>DIAGNOSIS: For cutaneous lesions a diagnosis by identifying organisms within cells on aspirate cytology (Wright’s or Giemsa stain) or histopathology of excised lesions is the method of choice. Although not reported in cats, PCR tests on infected tissues should be very sensitive and specific. </b></span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>IDENTIFICATION OF THE PARASITE:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> The amastigote stage of </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Leishmania tropica</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> is indistinguishable morphologically from other </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Leishmania</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> spp. and that of the </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Trypanosoma cruzi</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;">. The amastigote stage is round to oval, is 1.5 to 4.0 m in diameter, and contains a large nucleus and a smaller kinetoplast. The amastigotes appear slightly larger in impression smears than in histologic sections due to flattening and the different methods of fixation.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>LIFE CYCLE:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> Within the mammalian host the parasite grows and multiplies within macrophages and histiocytes of the skin at the site of the bite by the sandfly vector. </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Leishmania tropica</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> is transmitted between hosts by the bite of infected sandflies of the genus </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Phlebotomus</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;">. Within the sandfly are found the flagellated promastigote forms of the parasite that are similar to the stage found in cell-free cultures.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>CLINICAL PRESENTATION AND PATHOGENESIS:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> There is a report of two clinical cases of lesions of the </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Leishmania tropica</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> type in cats in Iraq (Machattie et al, 1931). These two cats were found to have ulcers and organisms that were identified as probably being due to </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Leishmania tropica</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;">. The cats appeared thin, but healthy. One cat had an extensive lesion on the nose, a small ulcerating sore on the left eyelid, and three papules on the left ear. The other cat had a single sore on its nose. Postmortem examination of the cats revealed no organisms within the deeper tissues. A cat from Marsellaise was found at autopsy to have numerous skin lesions that contained numerous organisms that were called </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Leishmania</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>infantum</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> (Dunan et al., 1989). The cat had presented to a local veterinarian with lesions that had began as erythematous lesions that later developed pustules. The lesions were on the top of the head and on the neck. After three months following anti-inflammatory and antibiotic therapy, the cat was euthanatized at the request of the owner. Only the skin lesions were submitted, thus, it was not possible to ascertainif there were organisms present in other body tissues.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>TREATMENT:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> There are no reports of attempted treatment of infected cats.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>EPIZOOTIOLOGY:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> Overall, very few cats have been examined for the presence of </span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><i>Leishmania tropica</i></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;">. It has been considered that they do not play a major role as mammalian hosts of this parasite, and at this time, it is believed that human beings serve as the major reservoir of infection.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>HAZARDS TO OTHER ANIMALS:</b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> Transmission to other animals is unlikely. Transmission could occur by direct inoculation of the organisms, but under most circumstances, this would probably not occur.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>HAZARDS TO HUMANS: </b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> Cats could serve as sources of human infection, but currently humans are considered to be major reservoirs of this parasite. However, personnel need to be protected from possible accidents that could introduce the organisms into their skin.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>CONTROL/PREVENTION: </b></span></span></span><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"> Control and prevention of the disease in cats would, in part, be based on reducing the number of cases within the human reservoir of infection.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><b>REFERENCES:</b></span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;">Dunan S, Mary C, Garbe L, Breton Y, Olivon B, Ferrey P, Cabassu JP. A propos d’un cas de leishmaniose chez un chat de la region Marseillaise. bull Soc Fran Parasitol 7:17-20.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;">Machattie C, Mills EA, Chadwick CR. Naturally occurring oriental sore of the domestic cat in Iraq. Trans Roy Soc Trop Med Hyg 25:103-332.</span></span></span></p> <p align="JUSTIFY"><span style="color: #000000;"><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;">Sergent E, Sergent E, Parrot LM, Dinatien AL, Béguet ME. 1921. Transmission do clou de Biskra par le phlébotome (Phlebotomus papatasi Scop.). Compt Rend Acad Sci 173:1030-1032.</span></span></span></p>