Phlebotomine sand flies (Diptera: Psychodidae) transmitting visceral leishmaniasis and their geographical distribution in China: a review.

After the existence of phlebotomine sand flies was first reported in China in 1910, the distribution of different species and their role in the transmission of visceral leishmaniasis (VL) have been extensively studied. Up until 2008, four species have been verified as vectors of VL, namely, Phlebotomus chinensis (Ph. sichuanensis), Ph. longiductus (Ph. chinensis longiductus), Ph. wui (Ph. major wui), and Ph. alexandri. The sand fly species vary greatly depending on the natural environments in the different geographic areas where they are endemic. Ph. chinensis is euryecious and adaptable to different ecologies, and is thus distributed widely in the plain, mountainous, and Loess Plateau regions north of the Yangtze River. Ph. longiductus is mainly distributed in ancient oasis areas south of Mt. Tianshan in the Xinjiang Uygur autonomous region. Ph. wui is the predominant species in deserts with Populus diversifolia and Tamarix vegetation in Xinjiang and the western part of the Inner Mongolia autonomous region. Finally, Ph. alexandri is steroecious and found only in stony desert areas, such as at the foot of the mountains in Xinjiang and the western Hexi Corridor, in Gansu province. This review summarized the relationship between the geographic distribution pattern of the four sand fly species and their geographical landscape in order to foster research on disease distribution and sand fly control planning. Furthermore, some problems that remained to be solved about vectors of VL in China were discussed.

Historical experience in the elimination of visceral leishmaniasis in the plain region of Eastern and Central China.

Visceral leishmaniasis (VL) (kala-azar) was most seriously prevalent in the plain regions of eight provinces/municipalities in the eastern and central parts of China. In the early 1950s, the number of counties/cities endemic for VL and the number of cases in the plain regions accounted for 60% and 80%, respectively, of the total numbers in the entire country. By implementing comprehensive control measures, including treatment of patients for eliminating the source of infection and spraying insecticide in endemic villages to kill sandflies, VL transmission has been brought under control in this region by the early 1960s, and no new infected cases have been found since 1983, achieving the goal of eliminating VL.

Discovery and study of cutaneous leishmaniasis in Karamay of Xinjiang, West China.

Cutaneous leishmaniasis (CL) was discovered in the farms of the Karamay suburb, Xinjiang Uygur Autonomous Region in the 1990s. Between 1992 and 1994, a house-to-house survey revealed a prevalence of 1.0-1.6% in the residents. The clinical types of skin lesions included papule, plaque, ulcer and nodular prurigo. Observations verified that, in some cases, the skin lesions healed spontaneously in 10-14 months, whilst in other cases, they persisted for several years. Sporadic cases of CL have continued to appear at the dermatology clinic of the local hospital since 2000. Phlebotomus wui (Ph. wui), subgenus Larroussius was confirmed as the transmitting vector. The causative agent is Leishmania infantum sensu lato.

[Prospect on the investigation of sandflies (Diptera: Psychodidae) in China].

Through literature review of the investigations on relevant sandflies (Dipter: Psychodidae) and his personal practical experience over the years, the author raises 5 issues referring to the taxonomy and biology of sandflies, density surveillance, transmission of Leishmania parasites, and their distribution status which need to be further studied, and the author looks forward to an attention from medical entomologists in China.

[Detection and species identification of two imported cases of cutaneous leishmaniasis].

OBJECTIVE: To diagnose and identify pathogen of two suspected cases of cutaneous leishmaniasis. METHODS: Two cases of dermatosis with several major ulcers on the skin were examined, who worked and returned from Algeria (case 1) and Saudi Arabia (case 2), respectively. The stained smears of skin tissue from lesions were observed by microscope. Extravasate from lesions was cultured in NNN medium to search protozoan parasites, which were obtained by centrifugation. Two pairs of species-specific primers, ITS1-ITS2 and K13A-K13B, were used to amplify inter-nal transcribed spacer of rDNA and kinetoplast DNA, respectively. The products were sequenced and analyzed by Blast. RESULTS: There were Leishmania amastigotes in the tissue smear of case 2, while none in that of case 1. Promastigotes were found in culture medium of both cases. The PCR products of ITS1-ITS2 and K13A-K13B from 2 cases were about 330 bp and 120 bp with respective homology of 100% and 96% to corresponding sequences of Leishmania major. The accession numbers of 4 sequences were JF831924-JF831927. CONCLUSION: Two cases of dermatosis are diagnosed as imported cutaneous leishmaniasis and the pathogen is L. major.

[Present situation of visceral leishmaniasis and prospect for its control in China].

Since the founding of the People's Republic of China, considerable success was achieved in visceral leishmaniasis (VL) control. By the end of 1970s, VL was effectively controlled from most endemic areas. However, VL has still been prevalent in some areas or sporadical cases reported in some other areas of 6 provinces/autonomous regions in western China, including Xinjiang, Gansu, Sichuan, Shaanxi, Shanxi and Inner Mongolia It is suggested that research activities be encouraged, including epidemiological factors, phlebotomine vector biology and control, wild animal hosts and disease relapse after treatment. Surveillance should be emphasized in the provinces/autonomous regions/municipalities where the disease has already been eliminated.

[Description of the ecological habits of Sergentomyia koloshanensis].

The ecological habit of Sergentomyia koloshanensis was investigated in Wenxian of Gansu Province and Nanping of Sichuan Province. This sandfly could be found from the last ten-day period of May to the first ten-day period of October, with a peak in the middle ten-day period of August. Its adult season covered as long as 4 and half months. It was exophilic with a vertical distribution reaching as high as 1640 m. At daytime, it rested in the caves and at the basal parts of boulder along the riverside, and it was difficult to find it in the residential areas; at night it moved about near the resting places, without human blood preference. By analyzing the available data of the description of sandfly species, it was found that Sergentomyia koloshanensis distributed mainly in the subtropical zone in China, with much less distribution in warm-temperate and marginal tropical areas.

[Differential diagnosis of visceral leishmaniasis, progressive disseminated histoplasmosis and penicilliosis marneffei].

Visceral leishmaniasis, progressive disseminated histoplasmosis and penicilliosis marneffei are infections found in both human and animals. Their clinical manifestations, morphology of the pathogens under microscope are similar. Misdiagnosis was common and prognosis was poor when wrong therapy was given. This article is to introduce the epidemiology, clinical manifestation, laboratory findings and the treatment of these infections.