A novel Dirofilaria species causing human and canine infections in Hong Kong.

Dirofilariasis is globally the commonest manifestation of zoonotic filariasis. We report the detection of a novel canine species causing human and canine dirofilariasis in Hong Kong. Three human cases occurring over 10 months were identified, one presenting with cervical lymphadenopathy, one with an abdominal subcutaneous mass, and one with a subconjunctival nodule. Transected worms recovered from the resected abdominal subcutaneous mass were morphologically compatible with Dirofilaria. The cox1 gene sequences of the three human isolates were identical; however, they were only 96.2% and 89.3% identical to the cox1 gene of Dirofilaria repens and Dirofilaria immitis, respectively. Sequencing of the 18S-ITS1-5.8S gene cluster was successful in the intact worm, and the nucleotide sequences were 94.0% and 94.9% identical to those of D. repens and D. immitis, respectively. Screening of the blood samples from 200 dogs and 100 cats showed the presence of the novel Dirofilaria species in 3% (6/200) of the dogs' but none of the cats' blood samples. Nucleotide sequences of the cox1 gene and 18S-ITS1-5.8S gene clusters of the dogs' samples were identical to those in the human samples. The sera of canines infected by this novel Dirofilaria species were negative when tested with the SNAP 4Dx D. immitis detection kit, except in the case of dogs with a mixed infection with D. immitis as detected by PCR. The results from this study suggest that this novel Dirofilaria species is a cause of filarial infection in humans and dogs in Hong Kong. We propose to name this Dirofilaria species "Candidatus Dirofilaria hongkongensis."

Diabetes and the outcome of infrainguinal bypass for critical limb ischaemia.

AIM: To examine the influence of diabetes mellitus (DM) on the outcome of infrainguinal bypass operations performed for critical foot ischaemia in Chinese patients. METHODS: A prospective audit of 265 consecutive infrainguinal bypass operations. RESULTS: Diabetic patients suffered more frequently from ischaemic heart disease (48% vs 25%, P=0.001) and tissue loss (90% vs 79%, P=0.01) at presentation. Cigarette smoking was more prevalent in the non-diabetic (NDM) group (72% vs 51%, P=0.001). Arterial segments distal to the common femoral artery were more often used as inflow to bypass graft in DM patients (36% vs 22%, P=0.02). Operative mortality (seven DM vs one NDM, P=0.19). Early graft failure (7% in DM group vs 10% in NDM group, P=0.24), wound infection rate (24% in DM group vs 17% in NDM group, P=0.21), early limb loss (9% in DM group vs 6% in NDM group, P=0.66) were comparable. However, hospital mortality was higher in DM patients (8% vs 1%, P=0.04). DM patients more frequently required further surgical debridement postoperatively (20% vs 9%, P=0.04). Long-term, patient survival was inferior in the DM group (43% NDM vs 33% DM at 5 years, P=0.03). Primary graft patency (46% DM vs 34% NDM at 4 years P=0.19), secondary graft patency (57% DM vs 47% NDM at 4 years P=0.14) and limb salvage rate (78% vs 81% at 5 years, P=0.79) were comparable. CONCLUSION: Diabetes mellitus adversely affects hospital mortality and long-term survival. Graft patency and limb salvage are not compromised by the presence of DM.