Bitten Patients Research Articles

Accessibility to rabies centers and human rabies post-exposure prophylaxis rates in Cambodia: A Bayesian spatio-temporal analysis to identify optimal locations for future centers.

Rabies is endemic in Cambodia. For exposed humans, post-exposure prophylaxis (PEP) is very effective in preventing this otherwise fatal disease. The Institut Pasteur du Cambodge (IPC) in Phnom Penh was the primary distributor of PEP in Cambodia until 2018. Since then, and to increase distribution of PEP, two new centers have been opened by IPC in the provinces of Battambang and Kampong Cham. Data on bitten patients, who sometimes bring the head of the biting animal for rabies analyses, have been recorded by IPC since 2000. However, human cases are not routinely recorded in Cambodia, making it difficult to establish a human burden of disease and generate a risk map of dog bites to inform the selection of future PEP center locations in high-risk areas. Our aim was to assess the impact of accessibility to rabies centers on the yearly rate of PEP patients in the population and generate a risk map to identify the locations where new centers would be the most beneficial to the Cambodian population. To accomplish this, we used spatio-temporal Bayesian regression models with the number of PEP patients as the outcome. The primary exposure variable considered was travel time to the nearest IPC center. Secondary exposure variables consisted of travel time to a provincial capital and urban proportion of the population. Between 2000 and 2016, a total of 293,955 PEP patient records were identified. Our results showed a significant negative association between travel time to IPC and the rate of PEP patients: an increase in one hour travel time from the living location to IPC PEP centers leads to a reduction in PEP rate of 70% to 80%. Five provinces were identified as the most efficient locations for future centers to maximize PEP accessibility: Banteay Meanchey, Siem Reap, Takeo, Kampot and Svay Rieng. Adding a PEP center in every provincial capital would increase the proportion of Cambodians living within 60 minutes of a PEP center from 26.6% to 64.9%, and living within 120 minutes from 52.8% to 93.3%, which could save hundreds of lives annually.

Risk of Attacks by Blackflies (Diptera: Simuliidae) and Occurrence of Severe Skin Symptoms in Bitten Patients along the Eastern Border of the European Union.

The components of blackfly (Diptera: Simuliidae) saliva secreted during feeding on humans and animals induce various pathological reactions manifested by skin lesions and systemic symptoms. In this study, we describe 43 cases of severe skin lesions induced by blackfly bites and analyze their potential causes. Based on the results of a survey of 418 patients, we identified periods with risk of blackfly attacks and their environmental determinants in the eastern part of the European Union. Especially strong inflammatory reactions after blackfly bites were reported in patients with concomitant cardiovascular diseases (mainly with venous insufficiency), metabolic diseases, and bacterial infections. Enhanced symptoms of simuliosis were also observed in other patients attacked by these insects only once or repeatedly. The greatest number of blackfly attacks in the study area is recorded from May to July, with a peak in June (38.73%) in the afternoon (37.10%) and evening (33.03%), when patients are in fields, forests, or their households. The case analysis indicates interactions of various factors in the development of severe inflammatory reactions in patients bitten by blackflies. Therefore, it is recommended that subjects exposed to the presence of blackflies during their work or rest should limit the length of their stay in a vulnerable environment during the highest seasonal and daily activity of these insects. It is also necessary to take measures to reduce the number of blackflies and popularize methods for prophylaxis of their attacks.

Transcriptomic Analysis of Salivary Glands of Ornithodoros brasiliensis Aragão, 1923, the Agent of a Neotropical Tick-Toxicosis Syndrome in Humans.

Tick salivary glands produce and secrete a variety of compounds that modulate host responses and ensure a successful blood meal. Despite great progress made in the identification of ticks salivary compounds in recent years, there is still a paucity of information concerning salivary molecules of Neotropical argasid ticks. Among this group of ticks, considering the number of human cases of parasitism, including severe syndromes and hospitalization, Ornithodoros brasiliensis can be considered one of the major Neotropical argasid species with impact in public health. Here, we describe the transcriptome analysis of O. brasiliensis salivary glands (ObSG). The transcriptome yielded ~14,957 putative contigs. A total of 368 contigs were attributed to secreted proteins (SP), which represent approximately 2.5% of transcripts but ~53% expression coverage transcripts per million. Lipocalins are the major protein family among the most expressed SP, accounting for ~16% of the secretory transcripts and 51% of secretory protein abundance. The most expressed transcript is an ortholog of TSGP4 (tick salivary gland protein 4), a lipocalin first identified in Ornithodoros kalahariensis that functions as a leukotriene C4 scavenger. A total of 55 lipocalin transcripts were identified in ObSG. Other transcripts potentially involved in tick-host interaction included as: basic/acid tail secretory proteins (second most abundant expressed group), serine protease inhibitors (including Kunitz inhibitors), 5' nucleotidases (tick apyrases), phospholipase A2, 7 disulfide bond domain, cystatins, and tick antimicrobial peptides. Another abundant group of proteins in ObSG is metalloproteases. Analysis of these major protein groups suggests that several duplication events after speciation were responsible for the abundance of redundant compounds in tick salivary glands. A full mitochondrial genome could be assembled from the transcriptome data and confirmed the close genetic identity of the tick strain sampled in the current study, to a tick strain previously implicated in tick toxicoses. This study provides novel information on the molecular composition of ObSG, a Brazilian endemic tick associated with several human cases of parasitism. These results could be helpful in the understanding of clinical findings observed in bitten patients, and also, could provide more information on the evolution of Neotropical argasids.

Epidemiology of Dog Bite Incidents in Chile: Factors Related to the Patterns of Human-Dog Relationship.

Simple SummaryDog bites are a major public health problem throughout the world. The main consequences for human health include physical and psychological injuries of varying proportions, secondary infections, sequelae, risk of transmission of zoonoses and surgery, among others, which entail costs for the health system and those affected. The objective of this study was to characterize epidemiologically the incidents of bites in Chile and the patterns of human-dog relationship involved. The results showed that the main victims were adults, men. The dogs most involved in these incidents were medium-sized, mixed-breed, and most of these were known to the victim. The greatest frequency of such episodes occurred inside the home. This characterization of the problem is essential for a comprehensive understanding of the topic to develop successful dog bite prevention and management programs.Dog bites are one of the main public health problems. They produce important consequences for those who suffer them (physical and psychological injuries, secondary infections, sequelae, risk of transmission of zoonoses and surgeries, among others). The objective of this study was to characterize epidemiologically the incidents of bites in Chile and the patterns of human-dog relationship involved. The records analyzed in this article were obtained from bitten patients who attended the main public health facilities in Chile during the period 17 September 2017 and 17 September 2018: In the period studied, 17,299 animal bites were recorded; however, only 7220 (41.74%) cases were analyzed in which the offending species could be identified. Of the bites analyzed, 6533 were caused by dogs (90.48%). Of these, 41.05% were caused by medium-sized dogs. Most bites were caused by dogs of mixed breeds (55.99%), followed by dogs of the German Shepherd breed (8.50%). Most of the dogs that bit were known to the victim (99.95%) and most of the attacks occurred indoors (57.48%). Although dog bite records have improved in Chile, it would be useful to also include background information on the context in which the incident occurred, which would be very useful for developing effective bite prevention programs.

Control of Cat Flea Infestation in Neonatal and Pediatric Intensive Care Units

Background In November 2015, our Infection Control Department was notified of flea infestation in neonatal and pediatric intensive care units (N&PICU) and flea bites among the units’ healthcare workers (HCWs).Methods We conducted an investigation in N&PICU. All sites, equipment, furniture, and unit and personal belongings were thoroughly inspected for fleas. The caught fleas were sent to the Division of Parasitology for further identification. Sources of flea transmission including host animals were searched for. The flea-bitten HCWs were examined for skin lesions and followed-up for development of systemic illnesses, such as severe allergic reactions and typhus.ResultsThe flea infestation was found in multiple sites of N&PICU including surfaces of unit belongings, non-medical equipment and walls. We found a couple kittens lying in the space for ventilator and air-conditioner pipes above the ceilings of N&PICU. Given the construction to build a new hospital building near N&PICU, parts of the pipe space were opened up and connected to the outside. This was most-likely the way the cats could get into the area and transmit the fleas. The caught fleas were identified under microscopic examination as Ctenocephalides felis (cat flea) (Figure 1). There were 4 patients and 41 HCWs bitten by the fleas. Single or multiple monomorphic erythematous papules sized 0.5–0.8 cm were found mainly over ankles, lower legs, forearms, neck, and upper back. The interventions to control the fleas included removal of the cats from the area, management of stray cats, closing the opening parts of the pipe space above the unit ceilings, mechanical removal of fleas, washing bedding, blankets and linens in hot water, and 2-hour steam fumigation throughout the units by portable machines (Figure 2) every 8 hours for 4 weeks. The attack rates were 44%, 3% and 0% before and after the first and second week of the interventions, respectively (P < 0.001). During 1-year follow-up, there had been no reports of additional flea infestation or any flea-related systemic illnesses among the bitten patients and HCWs.Conclusion Source control and intensive eradication of adult fleas and their eggs by steam fumigation were effective in control of cat flea infestation in the hospital units.Disclosures All authors: No reported disclosures.

Consultas por mordeduras de perro y seguimiento del animal en el sur de la ciudad de Salta, Argentina

A descriptive, cross-sectional study was carried out based on consultations of patients seen in the emergency room of a central hospital in a new operational area in the south of the city of Salta (Argentina) with 26 health centers reporting to it and offering coverage to about 200 thousand inhabitants. For the same coverage area, we registered the number of dogs entered to the Municipal Offi ce of Zoonosis for observation, according to the Observation Charts of Biter Animals which are enabled when the informer comes to the Offi ce and shows a police report or medical certifi cate (from public or private sector). Age distribution of bitten patients is strongly asymmetric-positive, which confi rms that pediatric population is more vulnerable to animal attacks. When the relation between sex and age groups was analyzed, no association was found between these variables for groups of children and adolescents; so age was independent of the sex of the bitten person (?2= 3.15; p=0.6764). In groups age 20 and older, women were signifi cantly more affected than men (?2= 8.65; p=0.0033). In the period studied, a rate of 1 biter animal was observed according to the procedure, every 7 bites seen at the hospital.

Syndromic Approach to Treatment of Snake Bite in Sri Lanka Based on Results of a Prospective National Hospital-Based Survey of Patients Envenomed by Identified Snakes

Of 860 snakes brought to 10 hospitals in Sri Lanka with the patients they had bitten, 762 (89%) were venomous. Russell's vipers (Daboia russelii) and hump-nosed pit vipers (Hypnale hypnale) were the most numerous and H. hypnale was the most widely distributed. Fifty-one (6%) were misidentified by hospital staff, causing inappropriate antivenom treatment of 13 patients. Distinctive clinical syndromes were identified to aid species diagnosis in most cases of snake bite in Sri Lanka where the biting species is unknown. Diagnostic sensitivities and specificities of these syndromes for envenoming were 78% and 96% by Naja naja, 66% and 100% by Bungarus caeruleus, 14% and 100% by Daboia russelii, and 10% and 97% by Hypnale hypnale, respectively. Although only polyspecific antivenoms are used in Sri Lanka, species diagnosis remains important to anticipate life-threatening complications such as local necrosis, hemorrhage and renal and respiratory failure and to identify likely victims of envenoming by H. hypnale who will not benefit from existing antivenoms. The technique of hospital-based collection, labeling and preservation of dead snakes brought by bitten patients is recommended for rapid assessment of a country's medically-important herpetofauna.

The clinical significance of venom detection in patients of cobra snakebite

Cobra snakebites are one of the most frequent occurrences among the poisonous snakebites. The correlation between the serum concentrations of cobra venom in the victims with the severity of systemic and local symptoms after envenoming is still awaited for investigation. In this paper, we have developed an enzyme-linked immunosorbent assay (ELISA) to detect Taiwan cobra venom existed in the serum of the cobra snakebite victims. This established technique allowed us to detect as low as 1 ng/ml. Totally, 31 serum samples of 27 recognized and suspected cobra snakebite patients were analyzed by the developed ELISA technique. The highest venom level detected was 1270 ng/ml in a case 2 h after being envenomed. We found that the serum concentrations of the venom in the bitten patients were well correlated with the severity of local tissue destruction. Venom levels might remain high 48 h after snakebite. Two or more vials of specific antivenom administered soon after snakebite were effective in neutralizing the circulating venom as revealed by ELISA. Higher doses of antivenom may be indicated in cases of cobra venom-induced local tissue destruction. In conclusion, these results indicate that venom detection in snakebite victims is valuable in diagnosis and severity assessment of Taiwan cobra snakebite.

Compared chemical properties of dermonecrotic and lethal toxins from spiders of the genus Loxosceles (Araneae).

Loxosceles spider venom usually causes a typical dermonecrotic lesion in bitten patients, but it may also cause systemic effects that may be lethal. Gel filtration on Sephadex G-100 of Loxosceles gaucho, L. laeta, or L. intermedia spider venoms resulted in three fractions (A, containing higher molecular mass components. B containing intermediate molecular mass components, and C with lower molecular mass components). The dermonecrotic and lethal activities were detected exclusively in fraction A of all three species. Analysis by SDS-PAGE showed that the major protein contained in fraction A has molecular weight approximately 35 kDa in L. gaucho and L. intermedia, but 32 kDa in L. laeta venom. These toxins were isolated from venoms of L. gaucho, L. laeta, and L. intermedia by SDS-PAGE followed by blotting to PVDF membrane and sequencing. A database search showed a high level of identity between each toxin and a fragment of the L. reclusa (North American spider) toxin. A multiple sequence alignment of the Loxosceles toxins showed many common identical residues in their N-terminal sequences. Identities ranged from 50.0% (L. gaucho and L. reclusa) to 61.1% (L. intermedia and L. reclusa). The purified toxins were also submitted to capillary electrophoresis peptide mapping after in situ partial hydrolysis of the blotted samples. The results obtained suggest that L. intermedia protein is more similar to L. laeta toxin than L. gaucho toxin and revealed a smaller homology between L. intermedia and L. gaucho. Altogether these findings suggest that the toxins responsible for most important activities of venoms of Loxosceles species have a molecular mass of 32-35 kDa and are probably homologous proteins.

Biological and Biochemical Properties of Venoms from Medically Important Loxosceles (Araneae) Species in Brazil

Abstract1. The biological, immunochemical and biochemical properties of venoms from Loxosceles gaucho, L. laeta and L. intermedia were studied.2. Venom from Loxosceles sp causes typical dermonecrotic lesion in bitten patients and rabbits but not in mice.3. The dermonecrotic and lethal activities of the L. gaucho venom were located in its higher mol. wt components (33.000–35.000).4. The higher molecular component of the venom is the most immunogenic component in both patients and rabbits.5. Analysis by SDS-PAGE showed the existence of many common components in the three venoms but no individual antigen was found.6. Antiserum to each one of these venoms was able to neutralize the dermonecrotic and lethal activities of all three venoms.7. Venom from L. gaucho has a significant adjuvant effect that was associated with its higher mol. wt components.8. The amino terminal sequence of 35 residues of L. gaucho active component was determined. A high level of identity (60%) and similarity (86%) was found between th...

Dermonecrotic and lethal components of Loxosceles gaucho spider venom

Loxosceles gaucho spider venom causes a typical dermonecrotic lesion in bitten patients and rarely causes lethal systemic effects. Gel filtration on Sephadex G 100 of L. gaucho spider venom resulted in three fractions: fraction A, containing the higher mol. wt components (approximately 35,000); fraction B, containing lower mol. wt components (approximately 15,000); and fraction C, containing very low mol. wt components (probably small peptides). The dermonecrotic and lethal activities were detected exclusively in fraction A. The venom and fraction A produced large dermonecrotic lesions in rabbits with necrosis spreading by gravity to the skin of the lateral body wall. Analysis by SDS-PAGE showed that the proteins contained in fraction A are approximately 35,000 and 33,000 mol. wt. Immunoblotting analysis showed that the proteins responsible for the dermonecrotic and lethal activity are very immunogenic and the first to be detected by antibodies during the course of immunization.

A national hospital-based survey of snakes responsible for bites in Thailand

Snakes which had been killed and brought to hospital with the patients they had bitten were collected in 80 district and provincial hospitals throughout 67 provinces in Thailand in order to establish the geographical distribution and relative medical importance of the venomous species. Of the 1631 snakes collected, 1145 were venomous: Malayan pit vipers ( Calloselasma rhodostoma), green pit vipers ( Trimeresurus albolabris) and Russell's vipers ( Daboia russelii) were the most numerous, while T. albolabris, C. rhodostoma and spitting cobras (‘ Naja atra’) were the most widely distributed. In 22 cases, non-venomous species were mistaken for venomous ones and antivenom was used unnecessarily. The Malayan krait ( Bungarus candidus) was confused with B. fasciatus in 5 cases and B. fasciatus antivenom was used inappropriately. The study extended the known ranges of most of the medically-important venomous species in Thailand. Correct identification of venomous snakes is especially important in Thailand because the locally-produced antivenoms are monospecific. The technique of hospital-based collection, labelling and preservation of dead snakes brought by bitten patients is recommended when rapid assessment of a country's medically important herpetofauna is required.