Re-emergence of canine Leishmania infantum infection in mountain areas of Beijing

Canine Leishmaniasis(CanL)is an endemic infectious disease in China,causing visceral Leishmaniasis(VL)and result-ing in important public health problem.However,in the last 3 y,endemic trends have changed considerably and spa-tial-temporal aggregation areas have shifted from northwestern to central China.Although Beijing was an endemic area for CanL in the last century,this disease has not been reported in Beijing since control programs were imple-mented in the 1950s.In the present study,PCR and immunochromatographic(ICT)were used to estimate prevalence of Leishmania infection in domestic dogs living in Beijing,a VL re-emergencearea.In total,4420 canine blood samples were collected at vet clinics in 14 districts of Beijing.Overall prevalence(percentage of dogs seropositive and/or PCR positive)of CanL infection in Beijing was 1.22%(54/4420).However,prevalence of CanL in the western mountain areas was 4.68%(45/961),significantly higher than that(0.26%,9/3459)of the plains.In addition,multilocus sequence typing(MLST)of seven enzyme-coding genes was used to examine phylogenetic relationships of CanL strains.Forty-one Leishmania infantum isolates were well separated from the other strains and divided into five major clades(A to E)by MLST analysis.All clades were closely related to strains from Sichuan Province and Gansu Province.A phylogenetic tree,based on the MLST,revealed that L.infantum in Beijing was genetically related to strains from western endemic of Mountain type VL in China.In conclusion,CanL has re-emerged in Beijing,and almost 5%of dogs living in Beijing’s mountain areas were infected with L.infantum.The phylogenetic tree based on MLST effectively distinguished species of Leishmania and reflected geographical origins.Because dogs are considered a natural reservoir,comprehensive control measures including surveillance,phylogenetic analyses and management should be implemented to mitigate or eliminate Leishmaniasis.

SRSF1 plays a critical role in invariant natural killer T cell development and function

Invariant natural killer T(iNKT)cells are highly conserved innate-like T lymphocytes that originate from CD4^(+)CD8^(+)double-positive(DP)thymocytes.Here,we report that serine/arginine splicing factor 1(SRSF1)intrinsically regulates iNKT cell development by directly targeting Myb and balancing the abundance of short and long isoforms.Conditional ablation of SRSF1 in DP cells led to a substantially diminished iNKT cell pool due to defects in proliferation,survival,and TCRαrearrangement.The transition from stage 0 to stage 1 of iNKT cells was substantially blocked,and the iNKT2 subset was notably diminished in SRSF1-deficient mice.SRSF1 deficiency resulted in aberrant expression of a series of regulators that are tightly correlated with iNKT cell development and iNKT2 differentiation,including Myb,PLZF,Gata3,ICOS,and CD5.In particular,we found that SRSF1 directly binds and regulates pre-mRNA alternative splicing of Myb and that the expression of the short isoform of Myb is substantially reduced in SRSF1-deficient DP and iNKT cells.Strikingly,ectopic expression of the Myb short isoform partially rectified the defects caused by ablation of SRSF1.Furthermore,we confirmed that the SRSF1-deficient mice exhibited resistance to acute liver injury uponα-GalCer and Con A induction.Our findings thus uncovered a previously unknown role of SRSF1 as an essential post-transcriptional regulator in iNKT cell development and functional differentiation,providing new clinical insights into iNKT-correlated disease.

Porphyromonas gulae infection in canines,pet owners and veterinarians in China:an epidemiological study and risk factor analysis

Porphyromonas gulae is a clinically prevalent,anaerobic,oral bacteria in canines,that may be a causative agent of canine periodontal disease,and a potential threat to human oral health.Research on P.gulae pathogenicity in canines,their owners,and veterinarians is lacking in China.This study aimed to determine the isolation and detec-tion rates of P.gulae in gingival crevicular fluid(GCF)samples from 101 canines in Beijing,using anaerobic culture techniques and 16S rRNA gene sequencing.The main risk factors for the transmission of P.gulae from canines to humans were also analyzed through analyzing the statistical data on risk factor variables from 103 canine owners and 60 veterinarians in Beijing who tested positive for P.gulae detection in GCF samples.The isolation and detection rates of P.gulae in canines were 31.5%(29/92)and 92.1%(93/101),respectively,compared with detection rates of 24.3%(25/103)in canine owners,43.3%(26/60)in veterinarians,and 52.0%(13/25)in dentists.The degree of contact with canines(P=0.001,P<0.01)and smoking(P=0.021,P<0.05)were significant risk factors for P.gulae detection in owners.Moreover,the degree of contact during ultrasonic scaling(P=0.065,0.05<P<0.1)was the most important risk factor for the positive detection of P.gulae in veterinarians.These findings suggest that P.gulae may colonize the human oral cavity through intimate contact with canines or participation in dental ultrasonic scaling operations.