Spatial analysis of visceral leishmaniasis in the oases of the plains of Kashi Prefecture, Xinjiang Uygur Autonomous Region, China.

BACKGROUND: Kashi Prefecture of Xinjiang is one of the most seriously affected areas with anthroponotic visceral leishmaniasis in China. A better understanding of space distribution features in this area was needed to guide strategies to eliminate visceral leishmaniasis from highly endemic areas. We performed a spatial analysis using the data collected in Bosh Klum Township in Xinjiang China. METHODS: Based on the report of endemic diseases between 1990 and 2005, three villages with a high number of visceral leishmaniasis cases in Bosh Klum Township were selected. We conducted a household survey to collect the baseline data of kala-azar patients using standard case definitions. The geographical information was recorded with GIS equipment. A binomial distribution fitting test, runs test, and Scan statistical analysis were used to assess the space distribution of the study area. RESULTS: The result of the binomial distribution fitting test showed that the distribution of visceral leishmaniasis cases in local families was inconsistent (χ(2) = 53.23, P < 0.01). The results of runs test showed that the distribution of leishmaniasis infected families along the channel was not random in the group of more than five infected families. The proportion of this kind of group in all infected families was 63.84 % (113 of 177). In the Scan statistical analysis, spatial aggregation was analyzed by poisson model, which found 3 spatial distribution areas 1) Zone A was located in a center point of 76.153447°E, 39.528477°N within its 1.11 mile radius, where the cumulative life-incidence of leishmaniasis was 1.95 times as high as that in surrounding areas (P < 0.05); 2) Zone B was located in a center point of 76.111968°E, 39.531895°N within its 0.54 mile radius, where the cumulative life-incidence of leishmaniasis was 1.82 times as high as that in surrounding areas (P < 0.01); and 3) Zone C was located in a center point of 76.195427°E, 39.563835°N within its 0.68 mile radius, where the cumulative life-incidence of leishmaniasis was 1.31 times as high as that in surrounding areas (P < 0.05). CONCLUSIONS: The spatial distribution of visceral leishmaniasis-infected families was clustered. Thus, the proper use of this finding would be an improvement in highly endemic areas, which could help identify the types of endemic areas and population at high risk and carry out appropriate measures to prevent and control VL in this area as well.

[Epidemiological Analysis of Imported Malaria in Xinjiang from 2004 to 2015].

Objective: To analyze the epidemiological characteristics of imported malaria in Xinjiang. Methods: The information of reported malaria cases and epidemiological records from various sources in Xinjiang Uygur Autonomous Region from 2004 to 2015 was collected. The epidemiological characteristics of malaria cases were analyzed. Results: Seventy-seven malaria cases were reported in Xinjiang from 2004 to 2015, and all were imported cases. In detail, 42 cases （54.5%） were reported during the time period of 2004-2009, with 24 laboratory diagnosed and 18 clinically diagnosed; 35 cases （45.5%） were reported from 2010 to 2015, with 27 laboratory diagnosed and 8 clinically diagnosed. Among the 51 cases with laboratory diagnosis, 18 were falciparum malaria, 31 were vivax malaria, and 2 unidentified. The male-to-female ratio was 6.7 ∶ 1（P<0.05）. The age range of the patients was 14-75 years （39.7 ± 13.3 years）, comprising 26.0% （20/77） for the range of 31-40 years and 24.7% （19/77） for the range of 41-50（P>0.05 among the age groups）. From the perspective of case sources, 28 cases （36.4%） were imported from Africa and 49 cases（63.6%） from Asia (including other provinces of China). The interval from onset to final diagnosis ranged 1-320 days. Only 3 patients（3.9%） were diagnosed within 24 h, and 59 patients（76.6%） were not diagnosed until or over one week. In addition, 28 cases（36.4%） were reported by medical institutions at the provincial level, 15 cases（19.5%） were reported by medical institutions at the prefecture level, 5 cases（6.5%） were reported by the Center for Disease Control and Prevention, and the rest 29 cases（37.7%） were reported at the county level or below. No secondary transmission was found. Conclusion: Most of the imported malaria cases during 2004-2015 were diagnosed with laboratory tests, reported by medical institutions, and were from Africa and Asia.

West nile virus infection in Xinjiang, China.

An outbreak of fever and meningitis/encephalitis occurred in Xinjiang, China, from August 5 to September 3, 2004. In preliminary diagnostic testing, several cerebrospinal fluid (CSF) and serum samples showed positive immunoglobulin M (IgM) antibody to Japanese encephalitis virus. Here, the CSF and serum samples of 6 cases collected at that time were tested by immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (ELISA), and plaque reduction neutralization assay (PRNT) for the existence of IgM antibody or neutralization antibody against West Nile virus (WNV) or other arboviruses. The results demonstrate the evidence of West Nile infection in Xinjiang, China.

Isolates of Liao ning virus from wild-caught mosquitoes in the Xinjiang province of China in 2005.

Liao ning virus (LNV) is related to Banna virus, a known human-pathogen present in south-east Asia. Both viruses belong to the genus Seadornavirus, family Reoviridae. LNV causes lethal haemorrhage in experimentally infected mice. Twenty seven isolates of LNV were made from mosquitoes collected in different locations within the Xinjiang province of north-western China during 2005. These mosquitoes were caught in the accommodation of human patients with febrile manifestations, or in animal barns where sheep represent the main livestock species. The regions where LNV was isolated are affected by seasonal encephalitis, but are free of Japanese encephalitis (JE). Genome segment 10 (Seg-10) (encoding cell-attachment and serotype-determining protein VP10) and Seg-12 (encoding non-structural protein VP12) were sequenced for multiple LNV isolates. Phylogenetic analyses showed a less homogenous Seg-10 gene pool, as compared to segment 12. However, all of these isolates appear to belong to LNV type-1. These data suggest a relatively recent introduction of LNV into Xinjiang province, with substitution rates for LNV Seg-10 and Seg-12, respectively, of 2.29×10(-4) and 1.57×10(-4) substitutions/nt/year. These substitution rates are similar to those estimated for other dsRNA viruses. Our data indicate that the history of LNV is characterized by a lack of demographic fluctuations. However, a decline in the LNV population in the late 1980s-early 1990s, was indicated by data for both Seg-10 and Seg-12. Data also suggest a beginning of an expansion in the late 1990s as inferred from Seg-12 skyline plot.

[Biological and phylogenetic analysis of first isolate of Tahyna virus in China].

In 2006, the first Chinese Tahyna virus isolate (XJ0625) was obtained in Xinjiang province and human infection were found in the same region. In this study, cell culture, animal experiments, electron microscopy, immunofluorescence assay and cross neutralization tests were performed to see the cell susceptibility, animal pathogenicity, morphology and antigenic and other biological characteristics of XJ0625. In addition, molecular biology software was used to analyze the characteristics of molecular evolution. The results showed that BHK-21 cell line was susceptible to XJ0625 and the virus was lethal to suckling mice when injected by intracranial ways. Similar to the other Bunyavirus, Tahyna virus is spherical enveloped virus under electron microscopy. XJ0625 infected cells showed strong fluorescent signal and could be neutralized by immune asities fluid with immnity to protype Tahyna virus Bardos 92. The sequence of the S and M segments showed 91.8% and 81.9% homology with Bardos 92.

An outbreak of the desert sub-type of zoonotic visceral leishmaniasis in Jiashi, Xinjiang Uygur Autonomous Region, People's Republic of China.

Few outbreaks of the desert sub-type of zoonotic visceral leishmaniasis (VL) have been described worldwide. In 2008, the incidence rate of VL in Jiashi County, Xinjiang Uygur Autonomous Region in the western part of the People's Republic of China, increased more than twenty-folds compared to the average annual incidence rate. The majority of the cases (96.6%) occurred among <2 year-old infants. For the first time in the desert area of Xinjiang, the parasites were isolated from bone marrow aspirates, using the NNN medium culture approach. The genetic analysis of the ITS-1 nucleotide sequence indicated that three isolates from eastern Jiashi County were genetically closely related and belonged to the Leishmaniainfantum group. However, they differed from an isolate from Kashi city which was classified as a member of the Leishmaniadonovani group.

[An epidemiological survey of visceral leishmaniasis in Hamangou coal mine area of Korla City, Xinjiang].

OBJECTIVE: To investigate the epidemiological status of visceral leishmaniasis in Hamangou coal mine area of Korla City of Xinjiang Uygur Autonomous Region. METHODS: Based on a hint of possible existence of patients, a retrospective survey was carried out house by house to find cases with suspected signs/symptoms of the disease. Meanwhile, a survey on current status was conducted, including physical examination (liver and spleen palpation) to those less than 15 years-old, leishmanin skin test and rk39 immunochromatographic strip test for part of the residents. Bone marrow smears were examined for the cases with clinical signs/symptoms and positive rk39 strip test. Sandflies were collected using routine methods in and around the area, identified, and dissected to find infection of promastigotes. RESULTS: Leishmanin skin test was performed in 185 people with a positive rate of 21.1% (39/185), 39 out of 140 local residents who have lived there for more than 6 years showed positive (27.9%), while all residents who have lived less than 6 years and children under 5 years old were negative. Of the 81 children under 15 years old with a negative skin test, one showed positive for rk39 strip test, and leishmania body was found in the bone marrow smear of this case, so confirmed as visceral leishmaniasis. 12 sandflies were identified as Phlebotomus alexandri, and natural infection with promastigotes was found in one sandly. CONCLUSION: The investigation confirms that visceral leishmaniasis is endemic in the Hamangou coal mine area.

[Study on time-space clustering regarding the distribution of visceral leishmaniasis in Kashgar Region, Xinjiang].

OBJECTIVE: To probe time-space clustering on the distribution of visceral leishmaniasis (VL) in Kashgar Region. METHODS: Based on the geographic information system, a Poisson model of time-space statistical software was applied to analyze data over the past 11 years in the Kashgar Region. Zones with clustering phenomenon were conformed by geographic location and remote sensing images. RESULTS: There existed three high risk clustering zones and corresponding time frames of VL in Kashgar Region. The center location of zone A was located in E 76.08 degrees, N 39.52 degrees, with radius as 6.58 km. The high risk time frame was from January 1st of 1999 to December 31st of 2003. Within the zone and time frame, the relative risk (RR) of VL incidence was 45.98 times higher than those outside the scope (P < 0.0001). Zone B' s center location was at E 79.20 degrees, N 39.91 degrees, with the radius as 4.93 km. Its high risk time frame was from January 1st of 2002 to December 31st of 2006. Within the zone and time frame, the RR of VL incidence was 9.58 times higher than those outside of the scope (P < 0.0001). Zone C' s center location was in E 76.23 degrees, N 39.40 degrees, and the radius was 7.63 km, with the high risk time frame from January 1st of 2000 to December 31st of 2004. Within the zone and time frame, the RR of VL incidence was 5.18 times higher than the one from outside of the scope (P < 0.0001). CONCLUSION: The incidence of VL in Kashgar Region was non-randomly distributed while there existed obvious time-space clustering, with all of three high risk clustering zones located in oasis area where appeared the focus area for control and surveillance of VL.

[A new member of Brevidensovirus, 0507JS11 virus isolated from Culex mosquitoes collected in Xinjiang].

OBJECTIVE: To probe the primary characteristic of 0507JS11 virus isolated from Culex sp. and determine the classification of 0507JS11 virus in taxonomy. METHODS: 0507JS11 virus was cultured in Aedes albopictus C6/36 cells and cytopathic effects (CPEs) were recorded. Electro-microscopic morphology of 0507JS11 virus was observed. Total DNA extract of 0507JS11 virus was detected by 1% Agarose Gel Electrophoresis. Complete genomic sequence of 0507JS11 virus was sequenced and then made phylogenetic analysis. RESULTS: 0507JS11 virus could cause CPEs in Aedes albopictus C6/36 cells. Viral particles have no envelope and appear icosahedron symmetry with diameter of 20 nm. The genome of 0507JS11 virus was positive single strand DNA (ssDNA) with full length of 3977 nt. However, a DNA band about 4 kbp was observed in the electrophoresis of total DNA extract of 0507JS11 virus. The coding region of the genome included three ORFs, ORF1 and ORF2 code NSP1 and NSP2, ORF3 codes VP. Phylogenetic analysis of the complete genomic sequence of 0507JS11 virus indicated an independent linear in Brevidensovirus. CONCLUSION: 0507JS11 virus is a new member in Brevidensovirus.

[Isolation and primary identification of viruses in mosquitoes in the south of Xinjiang].

OBJECTIVE: To isolate viruses from mosquitoes in the south of Xinjiang and identify these viruses primarily. METHODS: A total of 13 491 mosquitoes were collected in the south of Xinjiang from Jul to Aug, 2005. These mosquitoes were divided into 130 groups and grinded respectively. The supernates were inoculated in C6/36 and Vero cells. Viruses isolated were detected, the genomic nucleic types by electrophoresis of viral genomes and the morphologies observed under electronmicroscope. RESULTS: All 42 viruses were isolated, which caused CPEs on C6/36 but not on Vero cells. 27 viruses showed similar genomic profiles with 12 dsRNA segments. 1 virus displayed genomic profile with 10 dsRNA segments. 5 viruses took on similar genomic profiles with about 4 kbp DNA band. 9 viruses did not get any taxonomy information. Electromicroscopic pictures of these viruses revealed that above four types of viruses had distinguished morphologies indicating different virus species. CONCLUSION: There should be several virus species in the mosquitoes in the south of Xinjiang. dsRNA virus with 12 genomic segments should play analysis a predominant role in the south of Xinjiang.

[Investigation on echinococcosis in animals in Gannan Tibetan Autonomous Prefecture].

OBJECTIVE: To make an investigation on echinococcosis among animals in Gannan Tibetan Autonomous Prefecture. METHODS: 21 villages from Maqu and Luqu counties were selected for the survey in August of 2004-September of 2007. Rodents were trapped in the field. Sheep and yak livers, hearts and lungs were collected from the local slaughterhouses for pathological examination. Domestic dogs (shepherd dogs) were de-wormed by 15% arecoline to receive adult worms and stray dogs were shot for dissection. RESULTS: The prevalence of alveolar echinococcosis (AE) in Ochotona dahurica was 1.2% (1/87), and 2.3% (3/132) in Myospalax fontaniere, but no infection was found in Marmota himalayana, Ochotona tibetana and Mus musculus. 113 out of 1021 (11.1%) sheep were found infected with cystic echinococcosis (CE), and 3 (0.3%) with AE. 126 out of 634 (19.9%) yaks were infected with CE, and 2 yaks (0.3%) with AE. 17 out of 74 (23.0%) dogs were infected with Echinococcus granulosus (Eg), and 4 (5.4%) with Echinococcus multilocularis (Em). CONCLUSION: The results showed that there is a widespread endemic of Echinococcus granulosus in dogs and wild animals in Gannan Tibetan Autonomous Prefecture, with less Echinococcus multilocularis infection.

Tahyna virus and human infection, China.

In 2006, Tahyna virus was isolated from Culex spp. mosquitoes collected in Xinjiang, People's Republic of China. In 2007, to determine whether this virus was infecting humans, we tested serum from febrile patients. We found immunoglobulin (Ig) M and IgG against the virus, which suggests human infection in this region.

Isolation and characterization of the full coding sequence of a novel densovirus from the mosquito Culex pipiens pallens.

During an investigation of arboviruses in China, a novel densovirus (DNV) was isolated from the adult female Culex pipiens pallens. The virus, designated Culex pipiens pallens densovirus (CppDNV), caused cytopathic effect in C6/36 cells. The virus particles were icosahedral, non-enveloped and had a mean diameter of 24 nm. The complete coding region of CppDNV was found to be 3335 nt and it contained three open reading frames (ORFs). CppDNV shares 82-93 % identical nucleotides with isolates of the Aedes albopictus densovirus [isolates AalDNV-1, AalDNV-2 (C6/36 DNV) and AalDNV-3], Aedes aegypti densovirus (AaeDNV) and Haemagogus equines densovirus (HeDNV). The nucleotide sequence identity among CppDNV isolates exceeds 98 %. Phylogenetic trees based on non-structural (NS1 and NS2) and capsid (VP) genes show that CppDNV clustered with the species AaeDNV and represents a novel variant of this species within the genus Brevidensovirus.

[New type of cytoplasmic polyhedrosis virus isolated from mosquitoes in China].

0507BS3 virus was isolated from a mixed pool of Culex sp. and Anopheles sp. collected in Kashi, Xinjiang, China. 0507BS3 virus could cause cytopathic effects on C6/36 cells but not on Vero and BHK-21 cells. Viral particles had no envelope and appeared round with diameter of about 60 nm (n = 20). Viral capsid was composed of a single layer and a central core. Capsomeres on the surface of capsid were clearly visible. Electrophoresis of viral genome showed a profile of 10 double stranded RNA (dsRNA) segments. Sequencing of the tenth segment revealed the length of 964bp (GenBank ID: FJ150869). A single open reading frame (ORF) was found and encoded a protein of 275 amino acids with a molecular mass of 30.8kDa. The nucleotide sequence had no similarity with any other viral genomic sequences, but the deduced amino acid sequence significantly matched the polyhedrin genes of cytoplasmic polyhedrosis virus (CPV) in some sections. A phylogenetic tree was constructed to compare the polyhedrin gene sequences of all CPV types in GenBank. The tree demonstrated that 0507BS3 virus was only distantly related to the other CPV types and belonged to a new CPV type.

[0507JS60 virus isolated in Xinjiang was identified as Liaoning virus].

0507JS60 virus was isolated from a pool of Culex sp. collected in Kashi, Xinjiang, which could be propagated stably on C6/36 cells and caused cytopathic effects continuously. Viral particles had no envelope and appeared round with diameter of about 55nm (n = 10). Capsomeres on the surface of capsid were clearly visible. Electrophoresis of viral genome showed a profile of 12 double stranded RNA (dsRNA) segments. Sequencing of the twelfth segment revealed the length of 760bp (GenBank ID: FJ157354). A single open reading frame (ORF) was found and encoded a protein of 174 amino acids with a molecular mass of 18.9kD. The nucleotide sequence had similarity over 89% with that of LNV, but the deduced amino acid sequence had similarity over 91% with that of LNV. A phylogenetic tree was constructed to compare the corresponding genetic sequences in Seadornavirus. The tree demonstrated that 0507JS60 virus lied in the same branch with LNV and more closely related to LNV-NE9712. 0507JS60 virus was identified as LNV, which was firstly isolated outside the Northeast of China.

[A newly identified endemic area of visceral leishmaniasis in Minfeng county of South Xinjiang I. epidemiological survey].

OBJECTIVE: To investigate the epidemiological status of visceral leishmaniasis in Minfeng county, a newly identified endemic area in south Xinjiang, China. METHODS: Based on a hint of possible existence of patients, a retrospective survey was carried out house by house in Andier Township of the county to find cases with suspected signs/symptoms of the disease in the past 20 years including those died. Meanwhile, a survey on current status was conducted, including physical examination(liver and spleen palpation) to those under 15 years-old, leishmanin skin test and rk39 immunochromatographic strip test for part of the residents. RESULTS: The investigation covered 313 local residents and revealed no case with present illness but 60 cases with a history of suspected signs/symptoms including 13 deaths, traced back as visceral leishmaniasis. Leishmanin skin test was performed in 171 people with a positive rate of 99.4% and 28 out of 29 suspected cases showed positive (96.6%). rk39 immunochromatographic strip test was conducted in 197 people with a positive rate of 10.2% (20/197) and 19.4% (6/31) in those with a history of suspected signs/symptoms. CONCLUSION: The epidemiological investigation indicates that the Andier Township of Minfeng County is an endemic area of visceral leishmaniasis.

[Change of knowledge rate after health education on visceral leishmaniasis among residents in a township of Kashgar City].

Health education activities including distribution of brochures, posters, and lectures were conducted in selected villages of a kala-azar endemic-township, Kashi city of Xinjiang in 2004-2006. Questionnaire was carried out before and after health education in residents and students. The percentage of correctly answering all 5 questions on leishmaniasis in residents and primary/secondary school students increased from 0.7% and 0 to 54.2% and 70.7% respectively, indicating that health education can raise public awareness for the disease prevention and control.