Envenomation by the neotropical colubrid Boiruna maculata (Boulenger, 1896): a case report

This is a case report of a Boiruna maculata snake bite in a child admitted to the Hospital Municipal de Pronto Socorro de Porto Alegre, Porto Alegre, RS, Brazil. The patient was bitten on the lower left limb, and exhibited pronounced local manifestations of envenomation. She was treated with Bothrops antivenom and was discharged from the hospital five days later with marked improvement of envenomation.

Centipede (Scolopendra gigantea Linneaus 1758) envenomation in a newborn

The first case of centipede (Scolopendra gigantea Linneaus 1758) envenomation in a newborn is reported. When first examined, approximately 6 hours after the bite, the 28-day-old girl was irritable, with uncontrollable cry and intense local pain, oedema, local hyperthermia, and blood clots at punctures. Uncontrollable crying in neonates should rise the possibility of an insect or arachnid sting.

Proposal of abolition of the skin sensitivity test before equine rabies immune globulin application

An epizootic outbreak of rabies occurred in 1995 in Ribeirão Preto, SP, with 58 cases of animal rabies (54 dogs, 3 cats and 1 bat) confirmed by the Pasteur Institute of São Paulo, and one human death. The need to provide care to a large number of people for the application of equine rabies immune globulin (ERIG) prevented the execution of the skin sensitivity test (SST) and often also the execution of desensitization, procedures routinely used up to that time at the Emergency Unit of the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo (EU-UHFMRP-USP), a reference hospital for the application of heterologous sera. In view of our positive experience of several years with the abolition of SST and of the use of premedication before the application of antivenom sera, we used a similar schedule for ERIG application. Of the 1489 victims of animal bites, 1054 (71%) received ERIG; no patient was submitted to SST and all received intravenously anti-histamines (anti-H1 + anti-H2) and corticosteroids before the procedure. The patients were kept under observation for 60 to 180 minutes and no adverse reaction was observed. On the basis of these results, since December 1995 ERIG application has been decentralized in Ribeirão Preto and has become the responsibility of the Emergency Unit of the University Hospital and the Central Basic Health Unit, where the same routine is used. Since then, 4216 patients have received ERIG (1818 at the Basic Health Unit and 2398 at the EU-UHFMRP), with no problems. The ideal would be the routine use of human rabies immune globulin (HRIG) in public health programs, but this is problematic, because of their high cost. However, while this does not occur, the use of SST is no longer justified at the time of application of ERIG, in view of the clinical evidence of low predictive value and low sensitivity of SST involving the application of heterologous sera. It is very important to point out that a negative SST result may lead the health team to a feeling of false safety that no adverse reaction will occur, but this is not true for the anaphylactoid reactions. The decision to use premedication, which is based on knowledge about anaphylaxis and on the pharmacology of the medication used, is left to the judgment of health professionals, who should always be prepared for eventual untoward events.

Oral transmission of Chagas disease: importance of Trypanosoma cruzi biodeme in the intragastric experimental infection

Oral transmission of Trypanosoma cruzi has been suspected when epidemic episodes of acute infection were observed in areas devoid of domiciled insect vectors. Considering that the distribution of T. cruzi biodemes differs in sylvatic and domestic cycles, results of studies on biodemes can be of interest regarding oral transmission. The infectivity of T. cruzi strains of different biodemes was tested in mice subjected to infection by the digestive route (gavage). Swiss mice were infected either with the Peruvian strain (Biodeme Type I, Z2b) or the Colombian strain (Biodeme Type III, Z1, or T. cruzi I); for control, intraperitoneal inoculation was performed in a group of mice. The Colombian strain revealed a similar high infectivity and pathogenicity when either route of infection was used. However, the Peruvian strain showed contrasting levels of infectivity and pathogenicity, being high by intraperitoneal inoculation and low when the gastric route was used. The higher infectivity of the Colombian strain (Biodeme Type III) by gastric inoculation is in keeping with its role in the epidemic episodes of acute Chagas disease registered in the literature, since strains belonging to Biodeme III are most often found in sylvatic hosts.

Clinical and epidemiological features of definitive and presumed loxoscelism in São Paulo, Brazil

A retrospective study analysed 359 proven or presume cases of loxoscelism seen at the Hospital Vital Brazil, Instituto Butantan, São Paulo, Brazil, between 1985 and 1996. The spider was identified in 14%. The bites occurred predominantly in the urban areas (73%) between September and February. Patients > 14 years were commonest inflicted (92%) and 41% were bitten while getting dressed. Only 11% sought medical care within the first 12 hours post bite. Cutaneous loxoscelism was the commonest form presenting (96%); commonest manifestations were: pain (76%), erythema (72%), edema with enduration (66%), ecchymosis (39%). Skin necrosis occurred in 53% of patients, most frequently seen on trunk, tigh and upper arm, and when patients seek medical care more than 72 hours after bite. Local infection was detected in 12 patients (3%). Hemolysis was confirmed in 4 cases (1.1%). Generalised cutaneous rash, fever and headache were also observed in 48% of the total of patients. None of them had acute renal failure or died. Treatment usually involved antivenom administration (66%), being associated with corticosteroids (47%) or dapsone (30%). Presumptive diagnosis of loxoscelism may be established based on clinical and epidemiological findings. Further investigations are required to prove the value of antivenom and other treatment schedules.

First record of Desmodus rotundus in urban area from the city of Olinda, Pernambuco, Northeastern Brazil: a case report

The objective of this report is to describe the first record of Desmodus rotundus in urban area from the city of Olinda, Pernambuco State, Northeastern Brazil, and to draw attention to the possible risk of rabies transmission in this place. After the complaint of a dog owner who observed three bats attacking his dog, images registering attacks of D. rotundus were captured with a video camera. From 09:00 p.m. on 13 February 2004 to 04:00 a.m. of the next day, a high frequency of haematophagic activity and the presence of several bites on the dog's body were observed. This finding represents a serious risk to public health. Thus, it is necessary to further study the bat fauna, with special attention to their feeding behaviour in this place, in order to better know their biology and to adopt pertinent control measures. This is, to our knowledge, the first record of D. rotundus in urban area of Olinda.

Description of an injury in a human caused by a false tocandira (Dinoponera gigantea, Perty, 1833) with a revision on folkloric, pharmacological and clinical aspects of the giant ants of the genera Paraponera and Dinoponera (sub-family Ponerinae)

The authors observed an injury caused by the sting of a false tocandira ant in the hand of an amateur fisherman and they describe the clinical findings and the evolution of the envenoming, which presented an acute and violent pain, cold sweating, nausea, a vomiting episode, malaise, tachycardia and left axillary's lymphadenopathy. About three hours after the accident, still feeling intense pain in the place of the sting, he presented an episode of great amount of blood in the feces with no history of digestive, hematological or vascular problems. The intense pain decreased after eight hours, but the place stayed moderately painful for about 24 hours. In that moment, he presented small grade of local edema and erythema. The authors still present the folkloric, pharmacological and clinical aspects related to the tocandiras stings, a very interesting family of ants, which presents the largest and more venomous ants of the world.

Detection of Trypanosoma cruzi and Trypanosoma rangeli infection in triatomine vectors by amplification of the histone H2A/SIRE and the sno-RNA-C11 genes

Trypanosoma rangeli is non pathogenic for humans but of important medical and epidemiological interest because it shares vertebrate hosts, insect vectors, reservoirs and geographic areas with T. cruzi, the etiological agent of Chagas disease. Therefore, in this work, we set up two PCR reactions, TcH2AF/R and TrFR2, to distinguish T. cruzi from T. rangeli in mixed infections of vectors based on amplification of the histone H2A/SIRE and the small nucleolar RNA Cl1 genes, respectively. Both PCRs were able to appropriately detect all T. cruzi or T. rangeli experimentally infected-triatomines, as well as the S35/S36 PCR which amplifies the variable region of minicircle kDNA of T. cruzi. In mixed infections, whereas T. cruzi DNA was amplified in 100% of samples with TcH2AF/R and S35/S36 PCRs, T. rangeli was detected in 71% with TrF/R2 and in 6% with S35/S36. In a group of Rhodnius colombiensis collected from Coyaima (Colombia), T. cruzi was identified in 100% with both PCRs and T. rangeli in 14% with TrF/R2 and 10% with S35/S36 PCR. These results show that TcH2AF/R and TrF/R2 PCRs which are capable of recognizing all T. cruzi and T. rangeli strains and lineages could be useful for diagnosis as well as for epidemiological field studies of T. cruzi and T. rangeli vector infections.

Leishmania spp. parasite isolation through inoculation of patient biopsy macerates in interferon gamma knockout mice

Isolation of Leishmania parasite and species identification are important for confirmation and to help define the epidemiology of the leishmaniasis. Mice are often used to isolate pathogens, but the most common mouse strains are resistant to infection with parasites from the Leishmania (Viannia) subgenus. In this study we tested the inoculation of interferon gamma knockout (IFNγ KO) mice with biopsy macerates from Leishmania-infected patients to increase the possibility of isolating parasites. Biopsies from twenty five patients with clinical signs of leishmaniasis were taken and tested for the presence of parasites. Immunohistochemical assay (IHC) and conventional histopathology detected the parasite in 88% and 83% of the patients, respectively. Leishmania sp. were isolated in biopsy macerates from 52% of the patients by culture in Grace's insect medium, but 13% of isolates were lost due to contamination. Inoculation of macerates in IFNγ KO mice provides isolation of parasites in 31.8% of the biopsies. Most isolates belong to L. (Viannia) subgenus, as confirmed by PCR, except one that belongs to L. (Leishmania) subgenus. Our preliminary results support the use of IFNγ KO mice to improve the possibility to isolate New World Leishmania species.

Envenomation by Micrurus coral snakes in the Brazilian Amazon region: report of two cases

Two cases of proven coral snake bites were reported in Belém, Pará State, Brazil. The first case was a severe one caused by Micrurus surinamensis. The patient required mechanical ventilation due to acute respiratory failure. The second case showed just mild signs of envenomation caused by Micrurus filiformis. Both patients received specific Micrurus antivenom and were discharged without further complications. Coral snake bites are scarcely reported in the Amazon region and there is a broad spectrum of clinical manifestations, varying from extremely mild to those which may rapidly lead to death if the patient is not treated as soon as possible.

Genetic Control of Mosquitoes: population suppression strategies

Over the last two decades, morbidity and mortality from malaria and dengue fever among other pathogens are an increasing Public Health problem. The increase in the geographic distribution of vectors is accompanied by the emergence of viruses and diseases in new areas. There are insufficient specific therapeutic drugs available and there are no reliable vaccines for malaria or dengue, although some progress has been achieved, there is still a long way between its development and actual field use. Most mosquito control measures have failed to achieve their goals, mostly because of the mosquito's great reproductive capacity and genomic flexibility. Chemical control is increasingly restricted due to potential human toxicity, mortality in no target organisms, insecticide resistance, and other environmental impacts. Other strategies for mosquito control are desperately needed. The Sterile Insect Technique (SIT) is a species-specific and environmentally benign method for insect population suppression, it is based on mass rearing, radiation mediated sterilization, and release of a large number of male insects. Releasing of Insects carrying a dominant lethal gene (RIDL) offers a solution to many of the drawbacks of traditional SIT that have limited its application in mosquitoes while maintaining its environmentally friendly and species-specific utility. The self-limiting nature of sterile mosquitoes tends to make the issues related to field use of these somewhat less challenging than for self-spreading systems characteristic of population replacement strategies. They also are closer to field use, so might be appropriate to consider first. The prospect of genetic control methods against mosquito vectored human diseases is rapidly becoming a reality, many decisions will need to be made on a national, regional and international level regarding the biosafety, social, cultural and ethical aspects of the use and deployment of these vector control methods.

Envenoming by coral snakes (Micrurus) in Argentina, during the period between 1979-2003

Envenomation by coral snakes (Micrurus sp.) is one of the most dangerous injuries in America and it is considered as a serious medical emergency, however bites by these snakes appear to be rare. We analyzed epidemiological data, clinical signs and antivenom use in Argentina during the period between 1979-2003. During this period of study 46 non-fatal Micrurus bites were reported. The majority of cases were men from 31 to 40 years old. Bites occurred primarily in spring and summer. Most cases were reported from the northeast and northwest provinces of the country. The bites were mostly located on hands or feet and occurred mostly during agricultural activities and so mainly involved farmers. Only four cases occurred as a result of handling snakes. The median time it took for antivenom to be administrated was 60 minutes after the bite, and the median number of vials applied was 2. Local pain was mentioned and edema was reported in 41% of patients. All patients recovered without sequelae. This study showed a low incidence of Micrurus bites and low severity of envenomation. However, although no deaths have been reported during the last 30 years, given the toxicity of the venom of Micrurus snakes, the risk of severe envenomation should be considered.

SURVEY OF SANDFLY FAUNA (DIPTERA: PSYCHODIDAE) IN UBERLÂNDIA, MINAS GERAIS STATE, BRAZIL, 2003-2004

We analyzed the sandflies around houses and domestic animal shelters located in residences close to forests in localities on the banks of the Araguari River, Uberlândia, MG, from February 2003 to November 2004. The phlebotomines were captured in the peridomiciliary area, where Shannon traps were utilized in the peridomicile and CDC traps in animal shelters. 2,783 specimens of sandflies were captured, 2,140 females (76.9%) and 643 males (23.1%), distributed between 17 species. The most abundant species was Nyssomyia neivai (88.1%), followed by Nyssomyia whitmani (3.1%). The presence of Lutzomyia longipalpis was also confirmed, it is the main vector of Leishmania (L.) infantum chagasi which causes visceral leishmaniasis. The presence of species involved in the transmission of leishmaniases in the municipality of Uberlândia is cause for concern. The presence of L. longipalpis indicates that its urbanization may not have been aleatory and instead occurred through the destruction of wild ecotopes. More studies of their occupation in anthropic environments need to be made.

SEROLOGICAL SURVEY OF Ehrlichia SPECIES IN DOGS, HORSES AND HUMANS: ZOONOTIC SCENERY IN A RURAL SETTLEMENT FROM SOUTHERN BRAZIL

SUMMARY The aims of this study were to determine the seroprevalence of Ehrlichia spp. and risk factors for exposure in a restricted population of dogs, horses, and humans highly exposed to tick bites in a Brazilian rural settlement using a commercial ELISA rapid test and two indirect immunofluorescent assays (IFA) with E. canis and E. chaffeensis crude antigens. Serum samples from 132 dogs, 16 horses and 100 humans were used. Fifty-six out of 132 (42.4%) dogs were seropositive for E. canis. Dogs > one year were more likely to be seropositive for E. canis than dogs ≤ one year (p = 0.0051). Ten/16 (62.5%) and 8/16 (50%) horses were seropositive by the commercial ELISA and IFA, respectively. Five out of 100 (5%) humans were seropositive for E. canis and E. chaffeensis. Rhipicephalus sanguineus (n = 291, 97.98%) on dogs and Amblyomma cajennense (n = 25, 96.15%) on horses were the most common ticks found. In conclusion, anti-Ehrlichia spp. antibodies were found in horses; however, the lack of a molecular characterization precludes any conclusion regarding the agent involved. Additionally, the higher seroprevalence of E. canis in dogs and the evidence of anti-Ehrlichia spp. antibodies in humans suggest that human cases of ehrlichiosis in Brazil might be caused by E. canis, or other closely related species.

CHICKEN COOPS, Triatoma dimidiata INFESTATION AND ITS INFECTION WITH Trypanosoma cruzi IN A RURAL VILLAGE OF YUCATAN, MEXICO

This study longitudinally investigated the association between Triatoma dimidiata infestation, triatomine infection with Trypanosoma cruzi and household/backyard environmental characteristics in 101 homesteads in Molas and Yucatan, Mexico, between November 2009 (rainy season) and May 2010 (dry season). Logistic regression models tested the associations between insect infestation/infection and potential household-level risk factors. A total of 200 T. dimidiata were collected from 35.6% of the homesteads, mostly (73%) from the peridomicile. Of all the insects collected, 48% were infected with T. cruzi. Infected insects were collected in 31.6% of the homesteads (54.1% and 45.9% intra- and peridomiciliary, respectively). Approximately 30% of all triatomines collected were found in chicken coops. The presence of a chicken coop in the backyard of a homestead was significantly associated with both the odds of finding T. dimidiata (OR = 4.10, CI 95% = 1.61-10.43, p = 0.003) and the presence of triatomines infected with T. cruzi (OR = 3.37, CI 95% = 1.36-8.33, p = 0.006). The results of this study emphasize the relevance of chicken coops as a putative source of T. dimidiata populations and a potential risk for T. cruzi transmission.