Effectiveness of specific treatment of rabies. II. Analysis of cases of human death from rabies following a complete course of treatment with specific agents]

Of 79318 persons treated of rabies in the Uzbek SSR in 1968--1974 there were recorded 16 cases of death of clinically manifest rabies. The course of treatment included injection of rabies gamma-globulin in a dose of 0.5 ml per 1 kg of body weight and the maximal dose of rabies vaccine. The incubation period lasted from 44 to 833 days (229.6 on the average). The authors considered that irrational use of high doses of rabies preparations was the cause of unsuccessful treatment of rabies.     

Serologic survey for selected microbial pathogens of wolves in Alaska, 1975-1982

Serum samples were collected from 116 wolves which were captured in southcentral Alaska during 1975 through 1982. Antibodies to the following infectious disease agents were found: infectious canine hepatitis virus-72 of 87 (81%), canine parvovirus type 2-0 of 55 (0%) through 1979 and 10 of 32 (31%) after 1979, Francisella tularensis-16 of 67 (25%), canine distemper virus-10 of 83 (12%), Coxiella burnetti-5 of 95 (5%), rabies virus-1 of 88 (1%), Brucella spp.-1 of 67 (1%), Leptospira interrogans-1 of 82 (1%). Apparently rabies, brucellosis, and leptospirosis were rare and had little effect on the wolf population. Conversely, the other five infections were comparatively common and may have had a negative impact on the health of specific individual wolves, but did not appear to influence the health of the population.     

Rabies of wild mammals in Russia at the turn of the 20th and 21st centuries

Analysis of the incidence of animal rabies in Russia (1960–2006) and assessment of the abundance of wild canids and rabies infection prevalence among them (1981–2006) have been made. The results provide evidence for the dominant role of red foxes in the spread of rabies among wild animals (91.67%), which is confirmed by a strong correlation between the abundance of this predator and the numbers of infected animals (r = 0.73). In 2004 to 2006, the prevailing incidence of animal rabies in one or another territory was determined mainly (74.7%) by the pooled population density of red and corsac foxes and wolves. Natural and economic features of the landscape determined the incidence of rabies indirectly, via changes in the numbers of wild animals (by 68.9%). A comparative analysis of the recorded and potentially possible rabies incidence rates among wolves, red and corsac foxes, and raccoon dogs over the period from 1996 and 2006 is presented.     

Rabies Risk: Difficulties Encountered during Management of Grouped Cases of Bat Bites in 2 Isolated Villages in French Guiana

In French Guiana, from 1984 to 2011, 14 animal rabies cases and 1 human rabies case (2008) were diagnosed. In January 2011, vampire-bat attacks occurred in 2 isolated villages. In mid-January, a medical team from the Cayenne Centre for Anti-Rabies Treatment visited the sites to manage individuals potentially exposed to rabies and, in April, an anti-rabies vaccination campaign for dogs was conducted. Twenty individuals were bitten by bats in 1 month, most frequently on the feet. The median time to start management was 15 days. The complete Zagreb vaccination protocol (2 doses on day 0 and 1 dose on days 7 and 21) was administered to 16 patients, 12 also received specific immunoglobulins. The antibody titration was obtained for 12 patients (different from those who received immunoglobulins). The antibody titers were ≥0.5 EU/mL for all of them. The serology has not been implemented for the 12 patients who received immunoglobulins. Accidental destruction of a vampire-bat colony could be responsible for the attacks. The isolation and absence of sensitization of the populations were the main explanations for the management difficulties encountered. Sensitization programs should be conducted regularly.     

Immunogenicity and Safety in Adults of a New Chromatographically Purified Vero-cell Rabies Vaccine (CPRV): a Randomized, Double-blind Trial with Purified Vero-cell Rabies Vaccine (PVRV)

Recent improvements in chromatographic purification procedures have made it possible to develop a new chromatographically purified rabies vaccine (CPRV) by further purifying the current rabies vaccine prepared from Vero-cell culture (Verorab; Pasteur Mérieux Connaught). The immunogenicity and safety of primary immunization, followed by a booster at one year, with CPRV was compared to that of the purified Vero cell vaccine (PVRV) in a randomized, double-blind study carried out at four veterinary schools in France. A total of 330 healthy, male and female, first-year veterinary students, aged at least 18 years and who required pre-exposure rabies prophylaxis, were enrolled in this study. Included subjects were randomly assigned either CPRV (n = 163) or PVRV (n = 167) to be given as a primary immunization series of three intramuscular injections (D0, D7, D28), followed by a booster after 1 year (D365). Blood samples for serological analysis were taken at D0 (before first injection), D28, D42, D180, D365 (before booster) and D379. All subjects developed a strong immune response to the primary series, and at D42, all subjects had seroconverted for rabies neutralizing antibody (serum titre > or = 0.5 IU/ml). The rabies virus-neutralizing antibody GMT value at D42 in the CPRV group (23.0 IU/ml) was non-inferior to that in the PVRV group (29.6 IU/ml), according to a one-sided non-inferiority test. While antibody titres tended to decrease over the period of follow-up, at D365 (before booster), 97.5% subjects in the CPRV group and 98.8% of subjects in the PVRV group remained seroconverted. After booster, although the rabies antibody GMT value in the CPRV group was lower than that in the PVRV group, all subjects in both groups were seroconverted, and the difference is probably not clinically important. The incidence of local and systemic reactions tended to decrease with each dose during the primary immunization series, followed by a slight increase after booster (significant time-effect in an exploratory logistic regression analysis). Although mild or moderate local reactions tended to be more frequent after injection with CPRV compared to PVRV, systemic reactions were reported less often (significant group-effects in exploratory logistic regression analyses). One serious adverse event possibly related to vaccine occurred during this study (severe asthenia after the third dose of PVRV). This comparative study in healthy young adults demonstrates that the new chromatographically purified rabies vaccine is as immunogenic as PVRV, and seems to be associated with fewer systemic reactions.     

Rabies in skunks from Mexico.

An enzootic focus of rabies in skunks in Mexico is described. Fifty three wild animals including two badgers (Taxidea taxus), 32 bats (various species), one bobcat (Lynx rufus), two coatis (Nasua narica) three foxes (Urocyon cineroargenteus), one raccoon (Procyon lotor) and 12 skunks (see below) were tested for rabies by direct immunofluorescence assay from 1991 to 1997 in the central part of San Luis Potosi State, Mexico. Rabies occurrence was 21% of all tested mammals, with 19% in skunks and only 2% in other wild species (one bobcat). Skunks represented 23% of all mammals tested and had a rabies prevalence of 83%. Only 10 individuals were identified: three hog-nosed skunks (Conepatus leuconotus) and seven spotted skunks (Spilogale putorius). All were involved in human attacks; the spotted skunk attacks were inside bedrooms while people were sleeping, and the hog-nosed skunk attacks occurred outdoors. Skunk cases of rabies represented 40% of all rabies cases in 1997, and 100% of cases registered for wild animals in San Luis Potosi state. This situation constitutes an important public health problem and requires further epidemiological research to make the human population aware of the problem and to establish measures to limit further human attacks by rabid skunks.     

Plasma concentrations of gonadotrophins, preovulatory follicular development and luteal function associated with bovine follicular fluid-induced delay of oestrus in heifers

In Exp. 1, injections of 10 ml bovine follicular fluid (bFF, i.v. or s.c.), given twice daily for 3 days after injection of a luteolytic dose of PGF-2 alpha, delayed the onset of oestrus in 3 of 6 heifers to 8 or 9 days after PGF-2 alpha, as compared with 2 or 3 days after PGF-2 alpha in control heifers. Mean plasma concentrations of FSH and LH during the injection period were not different from those in saline-injected heifers. In Exp. 2, i.v. injections of 20 ml bFF twice daily for 3 days uniformly delayed oestrus to 8 days after PGF-2 alpha (N = 4) and injections of 20 ml bFF i.v. every 6 h for 24h on the day of PGF-2 alpha injection delayed oestrus to 5.0 +/- 0.6 days after PGF-2 alpha as compared with 2.8 +/- 0.3 days for control heifers. In both treatment groups, plasma concentrations of FSH were suppressed during the injection period and increased transiently after treatment, but plasma concentrations of LH during the injection period were not different from those of control heifers. Plasma levels of oestradiol in heifers given bFF remained basal for 2 or 3 days after treatment, then increased several days before the delayed oestrus, in a manner similar to that in control heifers, and elicited normal preovulatory surges of LH and FSH. Plasma concentrations of progesterone and the length of the next oestrous cycle were normal, indicating formation of functional corpora lutea. Therefore, bFF treatments appear to delay oestrus by selectively suppressing plasma FSH, without affecting LH, and delaying the development of the preovulatory follicle. These results suggest that FSH may be critical to support the growth and development of the preovulatory follicle after luteolysis in cows.     

Removing residual DNA from Vero-cell culture-derived human rabies vaccine by using nuclease

The clearance of host cell DNA is a critical indicator for Vero-cell culture-derived rabies vaccine. In this study, we evaluated the clearance of DNA in Vero-cell culture-derived rabies vaccine by purification process utilizing ultrafiltration, nuclease digestion, and gel filtration chromatography. The results showed that the bioprocess of using nuclease decreased residual DNA. Dot-blot hybridization analysis showed that the residual host cell DNA was <100 pg/ml in the final product. The residual nuclease in rabies vaccine was less than 0.1 ng/ml protein. The residual nuclease could not paly the biologically active role of digestion of DNA. Experiments of stability showed that the freeze-drying rabies virus vaccine was stable and titers were >5.0 IU/ml. Immunogenicity test and protection experiments indicated mice were greatly induced generation of neutralizing antibodies and invoked protective effects immunized with intraperitoneal injections of the rabies vaccine. These results demonstrated that the residual DNA was removed from virus particles and nuclease was removed by gel filtration chromatography. The date indicated that technology was an efficient method to produce rabies vaccine for human use by using nuclease.     

Loss of binding antibodies against rabies in a vaccinated dog population in Flores Island,Indonesia

Effective parenteral vaccines are available to control rabies in dogs. While such vaccines are successfully used worldwide, the period between vaccine boosters required to guarantee protection of the population against rabies varies between vaccines and populations. In Flores Island, Indonesia, internationally and locally produced rabies vaccines are used during annual vaccination campaigns of predominantly free-roaming owned domestic dogs. The study objective was to identify the duration of the presence and factors associated with the loss of adequate level of binding antibodies (≥0.5 EU/ml) following rabies vaccination in a domestic dog population on Flores Island. A total of 171 dogs that developed an antibody titre higher or equal to 0.5 EU/ml 30 days after vaccination (D30), were repeatedly sampled at day 90, 180, 270, and 360 after vaccination. On the day of vaccination (D0), an interview was performed with dog owners to collect information on dog characteristics (age, sex, body condition score (BCS)), history of rabies vaccination, kind of daily food, frequency of feeding, and origin of the dog. Serum samples were collected and the level of antibodies was quantitatively assessed using ELISA tests. Dogs were categorized as having an adequate level of binding antibodies (≥0.5 EU/ml) or inadequate level of binding antibodies (<0.5 EU/ml) at each time points examined. A total of 115, 72, 23, and 31 dogs were sampled at D90, D180, D270, and D360, respectively, with the highest proportion of antibodies ≥ 0.5 EU/ml (58%, 95% CI, 49–67%) at D90, which reduced gradually until D360 (35%, 95% CI, 19–52%). Multivariable logistic regression models showed that loss of adequate level of binding antibodies is significantly associated with dogs having no history of vaccination or vaccination applied more than 12 months before D0, being less than 12 months of age, and having a poor BCS. These results highlight the importance of BCS regarding the immune response duration and provide insights into frequency of vaccination campaigns required for the internationally available vaccine used on Flores Island. For dogs without vaccination history or vaccination being applied more than 12 months before D0, a booster is recommended within 3 months (a largest drop of antibodies was detected within the first 90 days) after the first vaccination to guarantee measurable protection of the population that lasts at least for one year.     

Individual attributes and party affect large carnivore attacks on humans

Wildlife managers, researchers and the general public have traditionally been demanding information on factors concerning the probability of risky encounters between predators and people, as well as how to react in those situations. This information is crucial to reduce the number of predator attacks, which in absolute terms have increased in the last decades. Here, we focus on the role of carnivore species and sex, as well as victim-related factors (i.e. gender, activities, party composition), as determinants of carnivore attacks on humans. Using a dataset on attacks by grizzlies (Ursus arctos horribilis), black bears (Ursus americanus), cougars (Puma concolor), wolves (Canis lupus) and coyotes (Canis latrans) in North America during the last five decades, we found that (1) male black bears were involved in attacks more frequently than females; (2) attacks by coyotes, cougars and wolves prevalently caused injuries, whereas cases of death were more frequent during grizzly and black bear attacks; and (3) people in a party were less vulnerable to an attack than a person alone. We identified risky situations and behaviours that should be avoided in areas where people and large carnivore share the landscape.     

Failure of interferon alfa and tribavirin in rabies encephalitis.

OBJECTIVE--To test the effect of interferon alfa and tribavirin (ribavirin) in patients with rabies encephalitis. DESIGN--An open trial of chemotherapy and intensive care in patients with early rabies. SETTING--The intensive care unit of a Bangkok hospital. PATIENTS--Four conscious men with clinical rabies encephalitis. INTERVENTIONS--Rapid virological diagnosis of rabies. Treatment with intravenous and intraventricular injections of high doses of lymphoblastoid interferon alfa in three patients and tribavirin in one patient. Intensive care was given throughout. MAIN OUTCOME MEASURES--Rabies infection confirmed by antigen detection and virus isolation. Rabies neutralising antibody and specific IgM sought in serum and cerebrospinal fluid. Interferon concentrations monitored before and during treatment in three patients. RESULTS--Interferon alfa treatment produced high concentrations in serum and cerebrospinal fluid. All four patients died after 5 1/2 to 12 1/2 days of treatment with no evidence of virostatic or clinically beneficial effects from either treatment. CONCLUSION--Interferon alfa treatment is not effective in rabies encephalitis. The use of tribavirin warrants further study, possibly combined with new therapeutic methods.     

Oral rabies vaccination of a northern Ohio raccoon population: relevance of population density and prebait serology

Ohio's oral rabies vaccination (ORV) program was established to prevent the westward spread of the raccoon (Procyon lotor) rabies virus (Lyssavirus, Rhabdoviridae) in Ohio, USA. The program, which targets raccoons, distributes vaccine-bait units (VBU) at a target density of 75 units/km2. Few studies have examined the relationship of VBU density and target population density to the prevalence of rabies virus-neutralizing antibodies (RVNA). We conducted experimental VBU distributions in August 2003 and August 2004, 150 km west of the ORV zone where there was no history of raccoon rabies. We measured change in RVNA titers in blood collected from live-trapped raccoons before and after VBU distributions. A closed population mark-recapture estimate of the size of the target population was 91 raccoons/km2, compared to the realized VBU distribution density of 70 units/km2. Surprisingly, 41% of 37 serum samples were RVNA-positive (>or=0.05 IU/ml) before VBU distribution in 2003, but all titers were <0.25 IU/ml. Although viable VBUs were distributed in August 2003, only 21% of 315 samples were RVNA-positive before VBU distribution in 2004, but 9% had titers>or=0.25 IU/ml. Tetracycline (biomarker in bait) prevalence in teeth indicated that 57% of raccoons ingested VBUs after distribution in 2003, and 54% ingested VBUs after distribution in 2004. However, only 8% and 11% of sera were positive for RVNA (>or=0.05 IU/ml) after VBU distribution in 2003 and 2004, respectively. Only 4-5% of sera collected after bait distribution had titers>or=0.25 IU/ml each year. The standard distribution density of 75 VBUs/km2 was insufficient to produce a population-wide immunoprotective response against rabies infection in our high-density target population. Presence of RVNA in a presumed na?ve population before baiting demonstrates that estimating prevalence of RVNA after oral rabies vaccination can be problematic without knowledge of background titers and seasonal changes in prevalence of RVNA before and after baiting.     

Treatment with inactivated cultured antirabies vaccine and antirabies gamma-globulin of persons biten by rabid wolves or those suspected of being rabid]

The authors present the results of using inactivated cultural rabies vaccine from the Vnukovo-32 strain in combination with rabies gamma-globulin for the treatment of 39 persons; of this number 28 were bitten by rabid wolves (the diagnosis was confirmed by laboratory methods), 25 had wounds of dangerous localization, and 3 were children from 7 to 15 years of age. In examining the sera of all the 39 bitten persons it was found that the scheme of combined vaccinations with inactivated cultural ribies vaccine and rabies gamma-globulin, officially acting in the USSR, in case of bites of dangerous localization led to formation of early continuous and lengthy passive and active immunity of adequate intensity.     

Short days and exogenous melatonin increase aggression of male Syrian hamsters (Mesocricetus auratus)

Many nontropical rodent species rely on photoperiod as a primary cue to coordinate seasonally appropriate changes in physiology and behavior. Among these changes, some species of rodents demonstrate increased aggression in short, "winter-like" compared with long "summer-like" day lengths. The precise neuroendocrine mechanisms mediating changes in aggression, however, remain largely unknown. The goal of the present study was to examine the effects of photoperiod and exogenous melatonin on resident-intruder aggression in male Syrian hamsters (Mesocricetus auratus). In Experiment 1, male Syrian hamsters were housed in long (LD 14:10) or short (LD 10:14) days for 10 weeks. In Experiment 2, hamsters were housed in long days and half of the animals were given daily subcutaneous melatonin injections (15 microg/day in 0.1 ml saline) 2 h before lights out for 10 consecutive days to simulate a short-day pattern of melatonin secretion, while the remaining animals received injections of the vehicle alone. Animals in both experiments were then tested using a resident-intruder model of aggression and the number of attacks, duration of attacks, and latency to initial attack were recorded. In Experiment 1, short-day hamsters underwent gonadal regression and displayed increased aggression compared with long-day animals. In Experiment 2, melatonin treatment also increased aggression compared with control hamsters without affecting circulating testosterone. Collectively, the results of the present study demonstrate that exposure to short days or short day-like patterns of melatonin increase aggression in male Syrian hamsters. In addition, these results suggest that photoperiodic changes in aggression provide an important, ecologically relevant model with which to study the neuroendocrine mechanisms underlying aggression in rodents.     

Genetic structure of expanding wolf (Canis lupus) populations in Italy and Croatia,and the early steps of the recolonization of the Eastern Alps

After centuries of range contraction and demographic declines wolves are now expanding in Europe, colonizing regions from where they have been absent for centuries. Wolf colonizing the western Alps originate by the expansion of the Italian population. Vagrant wolves of Italian and Dinaric-Balkan origins have been recently observed in the Eastern Alps. In this study we compared the genetic structure of wolf populations in Italy and Croatia, aiming to identify the sources of the ongoing recolonization of the Eastern Alps. DNA samples, extracted from 282 Italian and 152 Croatian wolves, were genotyped at 12 autosomal microsatellites (STR), four Y-linked STR and at the hypervariable part of the mitochondrial DNA control-region (mtDNA CR1). Wolves in Croatia and Italy underwent recent demographic bottlenecks, but they differ in genetic diversity and population structure. Wolves in Croatia were more variable at STR loci (N_A = 7.4, H_O = 0.66, H_E = 0.72; n = 152) than wolves in Italy (N_A = 5.3, H_O = 0.57, H_E = 0.58; n = 282). We found four mitochondrial DNA (mtDNA CR1) and 11 Y-STR haplotypes in Croatian wolves, but only one mtDNA CR1 and three Y-STR haplotypes in Italy. Wolves in Croatia were subdivided into three genetically distinct subpopulations (in Dalmatia, Gorski kotar and Lika regions), while Italian wolves were not sub-structured. Assignment testing shows that the eastern and central Alps are recolonized by wolves dispersing from both the Italian and Dinaric populations. The recolonization of the Alps will predictably continue in the future and the new population will be genetically admixed and very variable with greater opportunities for local adaptations and survival.     

Oral vaccination of raccoons (Procyon lotor) with an attenuated (SAD-B19) rabies virus vaccine

Unlike previous reports to the contrary, raccoons (Procyon lotor) were successfully vaccinated against rabies with a liquid SAD-B19 attenuated virus vaccine administered per os and given in vaccine-laden baits. There was neither evidence of vaccine-induced rabies in raccoons nor in a limited safety trial with opossums (Didelphis virginiana) given SAD-B19. Protection from lethal street rabies virus infection was not absolute: only three of nine raccoons given 1 x 10(6.0) TCID/ml were protected versus five of 10 raccoons given 1 x 10(7.0) TCID/ml of SAD-B19 and challenged 4 mo after consumption of vaccine-laden baits. Six of eight raccoons consuming 1 x 10(8.8) TCID/ml of SAD-B19 vaccine in baits survived street rabies virus challenge 2 mo postvaccination. Raccoon survivorship was not wholly dependent upon rabies virus-neutralizing antibody titer on the day of challenge. Vaccinated raccoons demonstrated a prominent anamnestic response within 1 wk following challenge. Surviving raccoons were observed for a minimum of 3 mo following street rabies virus challenge with neither clinical nor pathologic evidence of rabies. The SAD-B19 rabies vaccine administered within baits in captivity appears less effective for raccoons than for its demonstrated efficacy in the immunization of free-ranging foxes (Vulpes vulpes) in Europe.     

Oral vaccination of captive arctic foxes with lyophilized SAG2 rabies vaccine

Arctic foxes (Alopex lagopus) were immunized with lyophilized SAG2 oral rabies vaccine. The effectiveness of this vaccine was determined by serologic response and survival to challenge by rabies virus isolated from a red fox from Alaska (USA). No vaccine virus was found in saliva 1-72 hr after ingestion. At 2 wk after vaccination, all foxes had seroconverted, with rabies virus neutralizing antibody levels of 0.2-3.1 IU ml(-1). All vaccinated foxes survived to week 17 after challenge, and hippocampus, pons, and cerebellum were free of rabies virus as determined by direct immunofluorescence testing after death. One of four nonvaccinated foxes survived challenge and was free of rabies virus in neural tissue, and no rabies virus neutralizing antibody was detected in blood. Our results suggest that the lyophilized SAG2 oral rabies vaccine could be effective in arctic and subarctic regions, where freezing air and ground temperatures probably would not reduce its immunogenicity.     

Antibody Response to a Human Diploid Cell Rabies Vaccine

An experimentally killed rabies virus vaccine prepared in a human diploid cell strain (WI-38)—Wyeth rabies vaccine (WRV)—was used by various injection schedules in two separate studies to define more closely in human volunteer subjects an effective vaccination schedule for pre- or postexposure immunization, particularly for donors of rabies-hyperimmune plasma. To permit valid comparisons between our results and those of other workers, antibody levels achieved were expressed in terms of international units (IU) per milliliter of serum. Antibody response of previously nonvaccinated persons were only modest after a single dose of WRV, never reaching a level higher than 0.80 IU/ml over a 56-day testing period. Moreover, antibody was not detected at 0.16 IU/ml before the 14th day, either after a single dose or after two doses given 3 days apart. The best response followed four doses of WRV given within 4 weeks. This schedule resulted in the highest rate of seroconversion to the ≥6 IU/ml antibody level required of potential rabies-immune plasma donors. Giving the first vaccine dose in aluminum hydroxide diluent did not enhance the antibody response. There was a definite suggestion in the various injection schedules that higher and more sustained antibody levels were reached when the interval between the first and second vaccine doses was longest. The greater immunogenicity of WRV as compared with duck embryo vaccine was best demonstrated by the fact that a single booster dose of duck embryo vaccine to previously vaccinated individuals resulted in only a sevenfold antibody rise during the following 56 days, whereas a booster dose of WRV elicited a 69-fold rise. Al(OH)₃ in the first dose of WRV had no effect, but the enhancing effect of a longer interval between vaccine doses was noted once again; 20 of 20 subjects who received three doses of WRV with 4 weeks between doses developed good levels of rabies antibody, and 19 exceeded 6 IU/ml.     

Epizootic situation and measures for control of wild animals' rabies in Republic of Bashkortostan

Epizootologic characteristics of rabies incidence in the Republic of Bashkortostan for the period 1998 - 2006 are presented. Districts of Bashkortostan are divided on 3 zones according to severity of epizootic situation. Three years-cyclicity of rabies incidence with peak during winter was determined. Foxes, raccoons, wolves, lynxes, badgers, minks and, during recent years, corsacs are involved into the epizootic chain. Main source of rabies in the Republic is foxes with share of 91.9% among sick wild animals. During 1999-2006 8 cases of hydrophobia were registered. Results of analysis of effectiveness of oral immunization and regulation of wild fauna population are presented.