Extended leg infection of diabetic foot ulcers: risk factors and outcome.

OBJECTIVE: To identify the risk factors for extension of infection to the leg in diabetic foot ulcers (DFU) and to evaluate its role as a prognostic measure regarding limb salvage and healing time. METHOD: This retrospective case-control study took place in Jabir Abu Eliz Diabetic (JADC) during 2006-2008. Forty-eight patients diagnosed with a diabetic foot ulcer (DFU) with the infection extending to the leg (case group) were compared with an equal number of patients with a DFU without extension (control group). Risk factors for extension were identified by univariate analysis and both groups were compared with regard to limb salvage and healing time. RESULTS: Previous history of toe amputation was more frequent in the case group (p=0.004). The case group patients were significantly more likely to present with fever (p=0.01), pallor (p=0.02), confusion (p=0.04), and necrosis (p=0.004). Ulcers located in the heel were more frequent in the case group when compared with controls (p=0.0001) while more toes ulcers were found in the control group (p=0.001). A significant number of patients in the case group had an ulcer of more than 5cm diameter compared with those in the control group (p=0.001). The total number of patients presented with severe disease (Wagner grade 3-5) was significantly more in the case group compared with controls (p=0.004). Patients with severe infection (grade 4) were more in the case group compared with the controls (p=0.04). There were no significant differences between the two groups with regard to major and minor amputation rate. The case group had a longer duration of healing when compared with the controls. Seventy-five per cent of the controls healed by 6 months (n=31) compared with 22% in the case group (n=8 ; p=0.001). CONCLUSION: Toe amputation, wound located in the heel, wound size more than 5cm and advanced Wagner grade (3-5) and severe sepsis, grade 4, may be considered as risk factors for extension of infection to the leg in DFU. However, this extension did not carry a poor prognostic value to the final outcome if adequate therapeutic measures were followed.

Pre-acute hepadnaviral infection is associated with activation-induced apoptotic death of lymphocytes in the woodchuck (Marmota monax) model of hepatitis B.

Woodchucks (Marmota monax) infected with woodchuck hepatitis virus (WHV) represent a highly valuable immunopathogenic model of hepatitis B virus (HBV) infection. Both WHV and HBV are noncytopathic hepadnaviruses which induce a strong but delayed virus-specific cellular immune response believed to be a cause of hepatitis. The reason behind this postponement is not well understood and its dissection in the woodchuck model has been hampered by the lack of appropriate research tools. In this study, we applied an assay for the simultaneous detection of cell apoptosis and proliferation to determine the fate of T lymphocytes after WHV infection leading to acute hepatitis. The results revealed that pre-acute WHV infection is associated with the significantly heightened susceptibility of T lymphocytes to activation-induced apoptotic death. This suggests that T lymphocyte function is compromised very early in the course of hepadnaviral infection and this may directly contribute to the postponement of virus-specific T cell response.

A serological survey for Babesia in cattle in Scotland. III. The rates of acquisition and loss of antibody to Babesia and their effects on observed levels of antibody incidence.

Data for age and the incidence of antibody to Babesia divergens in cattle from areas of high and low endemicity have been analysed using three simple epidemiological models to estimate the rates of gain and loss of antibody. The models adequately described the observations but did not allow for an increased recovery rate attributable to acquired immunity in older animals. The rate of loss of babesial antibody in the absence of challenge was estimated directly from data for age and the incidence of antibody in Irish bred cattle located in nonendemic areas of Scotland. These data suggested an antibody loss rate of 0.25 per annum but did not provide firm evidence for the form of the antibody loss curve. Measurements of the titre of babesial antibody supported the conclusions drawn from studies of antibody incidence. In Irish bred cattle from non-endemic areas titres declined gradually over eight to ten years, whereas in cattle from an area of high endemicity, titres did not change appreciably with age. Cattle tested within one to three months of infection exhibited high titres.

The occurrence of antibody to Babesia and to the virus of louping-ill in deer in Scotland.

Sera of wild red deer from 16 localities in Scotland were tested by the indirect fluorescent antibody technique for antibody to Babesia and by the haemagglutination inhibition test for antibody to the virus of louping-ill. Babesial antibody was detected in sera from all localities in proportions ranging from 22 to 100 per cent. Antibody to louping-ill virus could not be demonstrated in sera from five of the localities and in the other 11 was found less frequently than was antibody to Babesia. Sera from male and female deer were positive for louping-ill in almost equal proportions whereas the incidence of babesial antibody was significantly lower in females than in mature males. This difference could be explained by the habits of the deer. The variable occurrence of louping-ill antibody suggested that red deer are tangential hosts for the virus.

The isolation and characterization of a Babesia from red deer (Cervus elaphus).

On three occasions, antibody positive blood from wild red deer produced overt infections with Babesia when inoculated into splenectomized red deer. One of the deer also became infected with Eperythrozoon sp. Babesia divergens, B. capreoli and the Babesia of red deer are morphologically similar and the marginal position of the parasites in the host cell is characteristic. Babesia were not seen and no antibody was formed in five out of six splenectomized bovine calves which were injected with parasitaemic red deer blood. Two of these calves when challenged with B. divergens were fully susceptible. A transient infection with the deer Babesia may have occurred in the sixth calf since antibody was detected and the animal resisted challenge with B. divergens. In indirect fluorescent antibody tests there was little or no difference in the titre of sera from naturally or experimentally infected cattle and deer when reacted with B. divergens or the red deer Babesia antigens. Despite their similarities, specific status for B. divergens and the red deer Babesia is probably justified; at present there is insufficient evidence to justify separation of the red deer Babesia from B. capreoli.

The number and morphology of trypanosomes in the blood and lymph of rats infected with Trypanosoma brucei and T. congolense.

The thoracic lymph duct of rats infected with Trypanosoma brucei and with T. congolense was cannulated at different stages of infection. Trypanosomes were always present in the lymph of rats infected with T. brucei, wheras they were absent or very scarce in the lymph of rats infected with T. congolense. There were greater fluctuations in the numbers of trypanosomes in the blood than in the lymph. The intra- and extravascular populations of T. brucei differed: stumpy forms were present only in blood; dividing forms were usually more numerous in lymph.

Differentiation of Trypanosoma brucei, T. rhodesiense, and T. gambiense by the indirect fluorescent antibody test.

Epidemiological studies, if they are to lead to appropriate preventive procedures, require knowledge of the host distribution of the parasite. Progress in the epidemiology of African trypanosomiasis is restricted by the lack of a reliable and simple method of differentiating Trypanosoma brucei, T. rhodesiense, and T. gambiense. The recently introduced blood inoculation infectivity test promises to fulfil this need by distinguishing T. brucei from T. rhodesiense, but it would not be suitable for separating T. brucei from T. gambiense, since rats and mice are frequently refractory to infection by fresh isolates of T. gambiense. Previous studies had indicated that the indirect fluorescent antibody test might differentiate not only the subgenera of the salivarian trypanosome species but also members of the subgenus Trypanozoon. A method of performing the test is described that enables T. brucei, T. rhodesiense, and T. gambiense to be differentiated by the titre of the sera. The method might be used in conjunction with the blood inoculation infectivity test to distinguish between new isolates of the subgenus Trypanozoon in East Africa, and also to search for possible animal reservoirs of T. gambiense in West Africa.