Density and behavior of capybara (Hydrochoerus hydrochaeris) ticks (Acari: Ixodidae) Amblyomma sculptum and Amblyomma dubitatum with notes on Rickettsia bellii infection: Assessing human exposure risk

In several urban and peri‑urban areas of Brazil, populations of Amblyomma sculptum and Amblyomma dubitatum ticks are maintained by capybaras (Hydrochoerus hydrochaeris). In some of these areas, this host and these tick species are associated with Brazilian spotted fever (BSF), a lethal human disease caused by the bacterium Rickettsia rickettsii. In this work, we evaluated the risk of human exposure to these tick species using four collection techniques to discern host-seeking behavior. The study was carried out in 10 urban sites inhabited by capybaras in Uberlândia, a BSF-free municipality in southeastern Brazil. Ticks were collected in areas of 400 m2 at each site and at three seasons. Within the same municipality, the distance and speed of A. sculptum nymphs moving towards the CO2 traps were evaluated. In a sample of ticks Rickettsia DNA was investigated. During the study period, 52,953 ticks were collected. Among these, 83.4 % were A. sculptum (1,523 adults, 10,545 nymphs and 32,104 larvae) and 16.6 % were A. dubitatum (464 adults, 2,153 nymphs and 6,164 larvae). An average annual questing tick density of 4.4/m² was observed, with the highest density recorded at one site in autumn (31.8/m²) and the lowest in summer at another site (0.03/m²). The visual search yielded the highest proportion of A. sculptum larvae, constituting 47 % of the total and 63.6 % of all A. sculptum larvae. In contrast, CO2 traps collected a greater proportion of nymphs and adults of A. sculptum ticks. In the case of A. dubitatum, the CO2 trap was the most efficient technique with 57.7 % of captures of this species, especially of nymphs (94.5 % of captures) and adults (97.8 % of captures). Ticks' ambush height on vegetation (9 to 77 cm), observed by visual search 30 times, yielded a total of 20,771 ticks. Of these, 28 (93 %) were A. sculptum ticks, with only two (7 %) identified as A. dubitatum ticks. Among A. sculptum ticks, the nymph was the most attracted stage to humans and larva in the case of A. dubitatum. Amblyomma sculptum adults and nymphs were significantly more attracted to humans than those of A. dubitatum, but A. dubitatum larvae were significantly more attracted than the same stage of A. sculptum. The maximum distance and speed of horizontal displacement for A. sculptum nymphs were five meters and 2.0 m/h, respectively. The only species of Rickettsia detected in ticks, exclusively in A. dubitatum, was R. bellii. Importantly, it was observed that the higher the proportion of A. sculptum in the community of ticks, the lower the rate of infection of A. dubitatum by R. bellii. In conclusion, host-seeking behavior differed between the two tick species, as well as between stages of the same species. A greater restriction of A. dubitatum ticks to the soil was observed, while larvae and nymphs of A. sculptum dispersed higher in the vegetation. The behavior presented by A. sculptum provides greater opportunities for contact with the hosts, while A. dubitatum depends more on an active search for a host, the hunter behavior. Taken together, these observations show that a human being crossing an area infested with A. sculptum and A. dubitatum ticks will have almost exclusive contact with A. sculptum larvae and/or nymphs. Humans in a stationary position (sitting, lying or immobile) are exposed to both tick species, but they are more attractive to adults and mainly nymphs of A. sculptum compared to the corresponding stages of the tick A. dubitatum. The negative effect of A. sculptum on A. dubitatum infection by R. bellii deserves further studies.

Canine Cystitis - Biofilm Formation by Bacterial Isolates

Background: Biofilms have been reported as important virulent markers associated with drug resistance in urinary tract infections (UTIs) in humans and dogs. However, in veterinary medicine, researches involving biofilm formation, treatments and preventions have been limited; yet, it is still possible to find few studies demonstrating biofilm-forming bacteria associated with different comorbidities such as otitis, wound infections, UTIs, and endometritis. These studies generally select dogs with chronic and recurrent infections, which could be an important factor in antibiotic resistance. We aimed to evaluate biofilms in sporadic cystitis regarding prevalence and drug resistance.Materials, Methods & Results: Urine samples were collected by cystocentesis from 36 client-owned dogs under clinical and laboratory suspicion of non-recurrent urinary bladder infection (cystitis). Urine was aseptically plated onto blood agar, MacConkey, and CLED, followed by incubation for 24 to 48 h. Definitive identification of a potential pathogen was made by subculture collected from an isolated colony to obtain a pure culture. The gram staining method and specific biochemical tests (phenol red fermentation, lysine, phenylalanine, citrate, sulfide-indole-motility, and urease) were used to distinguish and classify the bacteria. After identification, the bacteria were tested for antimicrobial susceptibility by a standard disk diffusion method, using the following antimicrobials: amoxicillin with clavulanic acid, ampicillin, ceftriaxone, ciprofloxacin, clindamycin, cefazolin, cephalothin, erythromycin, gentamicin, norfloxacin, and sulfamethoxazole-trimethoprim. The biofilm-forming ability was determined based on a culture in Congo red agar (CRA), where biofilm producer strains formed black colonies with a dry crystalline surface, while non-biofilm producer strains formed red colonies with a smooth surface. A crystal violet dye assay was used to confirm the CRA results. Of the 36 urine samples collected from dogs with suspected cystitis, a total of 37 isolates were obtained, from mixed or pure cultures. The most prevalent bacteria were Escherichia coli (11/37), followed by Staphylococcus spp. (8/37), Proteus spp. (7/37), and Enterococcus spp. (5/37). Other less prevalent bacteria were Klebsiella spp., Streptococcus spp., and Enterobacter spp. As for biofilm-forming ability, 67.6% (25/37) of the 37 bacterial isolates had biofilm formation in CRA and 54.05% (20/37) on the microplates containing crystal violet dye. There was no statistical difference in antimicrobial susceptibility between biofilm producer and non-biofilm producer bacteria.Discussion: We found a high proportion (> 54%) of in vitro biofilm-forming ability by different bacteria, which may indicate that biofilms may also be formed in vivo, in simple cystitis. Antimicrobial resistance was not noticed in bacteria capable of forming a biofilm; however, in a future study it is important to evaluate bacterial resistance in vivo, considering the possibility of having a different response than in vitro. In addition, the problem of the presence of a biofilm in vivo is that it can nullify the antimicrobial efficacy of therapeutic agents even with in vitro susceptibility. Besides the possibility of slow or incomplete diffusion of antibiotics through the extracellular matrix of the biofilm, aspects like hydration level, pCO2, pO2, pH, pyrimidine, and divalent cation concentration that negatively influence antimicrobial activity in vitro can also cause undesirable effects at the profound layers of the biofilm. In conclusion, all of the genera of bacteria isolated from dog’s sporadic cystitis in this study were able to form a biofilm in vitro. The pathogenicity and antibiotic resistance of bacteria appears unrelated to biofilm formation in vitro.Keywords: sessile bacteria, urine, simple cystitis, antibiotic resistance.

Caseous Stomatitis Caused by Pseudomonas aeruginosa in Boa constrictor amarali

Background: Pseudomonas aeruginosa is a bacterium that belongs to the microbiota of snakes, but it may also be an opportunistic pathogen and contaminate humans through fecal contact, bites, and injuries. In snakes, this microorganism may present high pathogenicity at certain conditions and have been associated with high morbidity and mortality. Reports of infection of Boa constrictor by this pathogen are rare. Thus, this study aimed to describe the P. aeruginosa oral infection in a snake specimen (Boa constrictor amarali), approaching the isolation and identification of the infectious agents involved, the antimicrobial sensitivity and resistance, and the therapeutic protocol adopted.Case: A free-living adult female specimen of Boa constrictor amarali (Amaral's boa), with no described previous history was rescued in an urban area by the Environmental Police. Clinical evaluations showed structures of caseous aspect in the oral cavity, with hyperemia spots in the mucosa. Samples of these lesions were sent for mycological examination, and fungal forms were not found. Samples were collected for isolation and culture. The antimicrobial susceptibility of the isolated microorganisms was determined by the modified Kirby-Bauer disk diffusion method. P. aeruginosa was isolated and showed susceptibility to amikacin, gentamicin, and polymyxin-B; intermediate susceptibility to azithromycin, and ciprofloxacin; and resistance to cephalexin, ceftiofur, chloramphenicol, and enrofloxacin. The treatment consisted of cleaning of the oral cavity, local infiltration of lidocaine for debridement of the caseous area that were later cauterized with iodine. Systemic antibiotic therapy was used, with intramuscular administration of amikacin (5 mg/kg) for the first dose and (2.5 mg/kg) for the other doses with intervals of 72 h, and oral administration of metronidazole (20 mg/kg) with intervals of 48 h, both during 21 days. Daily subcutaneous fluid therapy was performed as support treatment, using Lactated Ringer's solution (25 mg/kg) and Vitamin C (10 mg/kg) with intervals of 24 h, being the cure observed at the end of treatment.Discussion: This paper presents the pathological findings of the Pseudomonas aeruginosa oral infection in a B. constrictor amarali. This bacterium is an opportunistic pathogen that is commonly found  in snakes, thus, humans in contact with these animals may be contaminated with this pathogen. However, oral cavity lesions associated with P. aeruginosa had not yet been related to Boa constrictor amarali, which is a non-venomous species. Few bacteria associated with reptile diseases are primary causative agents. Clinical bacterial infections generally tend to be secondary to viral infections. Predisposing factors for the development of bacterial diseases in these reptiles include immunodepression, malnutrition, poor adaptation to captivity, and the maintenance of these animals at temperatures and humidities outside their thermal comfort range. In the present study, the P. aeruginosa behaved as an opportunistic pathogen, resulting in clinical manifestations with caseous lesions in the oral cavity, probably due to an imbalance of the microbiota caused by stress or immunodepression. The antibiogram allowed the adoption of a correct therapeutic protocol based on the susceptibility of the pathogen, resulting in remission of lesions and clinical signs after 21 days of treatment.

Free-living Capybaras (Hydrochoerus hydrochaeris) in an Urban Area in Brazil - Biochemical and Hematological Parameters

Background: Capybaras have found favorable conditions for survival and reproduction in green urban environments. In recent years, the population of these large rodents has been increasingly abundant in several brazilian cities such as Uberlândia, a municipality of the southeastern region with a Cerrado biome. Capybaras are important in the Brazilian Spotted Fever epidemiological chain, by amplifying infection rates of the vector population. However, knowledge of this host´s physiology is scarce. Thus, the aim of this work was to describe hematological and biochemical parameters of free-living capybaras groups in urbanized areas in the city of Uberlândia, Minas Gerais State, Brazil.Materials, Methods & Results: Capybaras were captured in 4 different locations of Uberlândia city, Minas Gerais state, including 1 Condominium (P1), 1 Private Market Garden (P2), 1 Private Club (P3) and 1 Municipal Park (P4). The animals were baited into an octagonal iron corral and chemically contained with anesthetic darts. After sedated, blood was collected from the femoral vein in tubes with and without EDTA. Biochemical evaluation, hematological analysis with differential leukocyte counts and search for Dirofilaria sp. were done. The blood count and biochemistry values obtained from animals of different ages, sex and sectors (P1, P2, P3 and P4) were submitted to the Shapiro-Wilk normality test, considering 95% significance. Values that had a normal distribution were subjected to ANOVA tests followed by Student's t-test. Values that did not follow normality were submitted to the Kruskal-Wallis test, to obtain a P-value, with a significance level of 95%. A total of 19 capybaras were captured: 4 in P1, 6 in P2, 4 in P3 and 5 in P4. From the 19 animals, 13 were females (68.42%) and 6 were males (31.57%), 12 adults (63.15%) and 7 juveniles (36.84%). Apart from occasional skin scars and moderate to intense Ambyomma spp. tick infestations, all captured animals were healthy on a broad examination. From 5 animals captured in P4, despite the use of anticoagulant, blood from 4 animals clotted fast. No microfilariae were found in the thick drop test in any of the 19 animals sampled, and in 2 adult female capybaras captured in P1, Kurloff cells were observed. Hematological and biochemical values presented no major differences when comparing sex and age. Nevertheless, differences in liver and kidney profile were observed between the capybara groups, including ALT, alkaline phosphorus, BUN and creatinine.Discussion: Blood from 4 animals clotted fast, despite the use of EDTA tubes. Blood clotting of samples with anticoagulant in this work could be associated with some physiological features inherent to capybaras. Many attempts were required to obtain enough blood from each individual due to the rapid hemostasis, what come in accordance with reports in literature. Kurloff cells were observed in 2 adult female capybaras captured in P1, which can be found in peripheral blood of female rodents during follicular phase of estrous cycle. Hematological and biochemical values differences in liver enzymes such as ALT and alkaline phosphorus, and kidney profile enzymes including BUN and creatinine could be associated to capture stress or dietetic variation between groups. Despite statistical relevant, the values were still in accordance with other works, although comparisons should be done with caution since various environments exert a diverse array of stimulus upon the animals such as parasitic, infective, stress, nutritional, social and undoubtedly blood parameters mirror them. In conclusion, this work contributes to the standardization of free-living capybaras' physiological parameters in urban areas.Keywords: capybaras, physiological parameters, enzymatic parameters, green urban environment, capture stress, fauna, biomes. 

Green Anaconda (Eunectes murinus) with Bacterial Clinical Stomatitis

Background: Stomatitis is an infectious disease common in serpents and responsible for high mortality rates. It is characterized by the infection of the oral mucosa and neighboring tissues, related to the opportunistic character of bacteria present in the normal microbiota, pathogenic in stressful situations. Few studies have described the profile of sensibility of these agents in serpents of the Brazilian fauna. Therefore, this study has aimed at describing the isolation and identification of the infectious agents involved in the clinic stomatitis in a specimen of green anaconda (Eunectes murinus), and the profile of susceptibility to antimicrobial agents.Case: The serpent has been rescued in an urban environment, without previous records and featured erosive injuries in its oral cavity, with the presence of secretion. In a clinical evaluation, it has been assessed that the specimen had erosive injuries in its oral cavity, with hyperemic points in its mucosa and serous secretion. Then the specimen went through a collection of the secretion from its oral cavity for microbiological analysis. Typical colonies of Enterococcus, Citrobacter and Enterobacter were identified by the colony morphology and their typical odor. The results of these tests were able to confirm and identify the Citrobacter freundii, Enterobacter spp. and Enterococcus spp. The profile of sensibility to antimicrobials of the isolated microorganisms has been determined through the method of diffusion in the disk of Kirby-Bauer. There was not any sensitive antimicrobial drug for the three agents.Discussion: Immunodepression, malnutrition, and temperatures and humidity outside the animal thermal comfort zone, are predisposing factors for the development of bacterial diseases in reptiles. Little information about pathogen agents affecting constrictor serpents in their native area is available. Most reports on stomatitis in serpents approach cases occurred in captive animals, differently from what has been presented in this case, which is about a free animal rescued when invading an urban area. The bacteria isolated from the oral cavity of the serpent here reported belong to the normal microbiota of the oral cavity of these animals. Notwithstanding, these bacteria may become pathogenic in certain circumstances. Conditions of undernutrition, stress and oral trauma are considered as predisposing factors to the occurrence of stomatitis in serpents, what can be correlated to the occurrence of the disease in this case. The gram-negative agents causing bacterial diseases in serpents are generally resistant to medicines of the most common spectrum used in the clinical routine of wild animals. This way, veterinarians often deal with these diseases in reptiles empirically, using a wide range of antibiotics. This practice might result in the development of resistant bacterial stumps, what stands out due to the potential that resistant bacteria have to generate infections and zoonoses in humans.

Dermatopathy Caused by Enterobacter aerogenes and Pseudomonas aeruginosa in Boa constrictor amarali

Background: Bacterial diseases are the main cause of the high mortality rates of snakes, especially those caused by gramnegative agents. However, studies on dermatopathy caused by these bacterial agents in snakes are scarce; and no reports have been found on Enterobacter aerogenes as causative agent of dermatopathy in snake species. Thus, the objective of this study was to describe the clinical signs, and lesion evolution of a dermatopathy in a male snake (Boa constrictor amarali) specimen of approximately seven years old; and to describe the isolation and identification of the Enterobacter aerogenes and Pseudomonas aeruginosa agents involved in the cause of this disease.Case: The Boa constrictor amarali evaluated presented blackened cutaneous lesions in the dorsal, snout-vent and tail regions; and well-defined subcutaneous nodules of 2.0-3.0 cm diameter, with soft consistency, reddish color, cutaneous flaccidity, and areas of scale ulceration in the dorsolateral region. The clinical evaluation of the animal showed dehydration signs and pale mucous membranes. The blackened lesions were subjected to mycological analysis - after procedure of deep scale scraping - which showed presence of septate hyphae. The nodule was punctured for microbiological and biochemical analysis. The sample was collected with a sterilized alginate cotton tip swab, and was stored in a plastic tube containing a semi-solid Stuart transport medium, for microbiological analysis. Then, this sample was incubated in a bacteriological oven at 37°C for 24 h. Typical colonies of Pseudomonas and Enterobacter grew on MacConkey agar medium; these bacteria were identified by the colony morphology and their typical odor. The colonies grown in MacConkey agar were also identified through biochemical tests in the mediums: Phenol red, Lysine, Phenylalanine, Citrate, Urea and SIM (Sulfide, Indole, Motility). The results of these tests were able to confirm and identify the P. aeruginosa and E. aerogenes species. The animal died within 36 h, before the identification of the causative agents of the disease, thus, no pharmacological interference was possible.Discussion: Immunodepression, malnutrition, and temperatures and humidity outside the animal thermal comfort zone, are predisposing factors for the development of bacterial diseases in reptiles. Little information about pathogen agents affecting Boa constrictor specimens in their native area is available; however, captive snakes are subject to a wide variety of diseases - most of which caused or intensified by the captivity conditions. Among the bacteria involved in reptile diseases, few are primary causative agents. In general, clinical bacterial infections tend to be secondary to viral infections. The bacterial agents found in this study are commonly described in scientific literature with location in the oral cavity, differently from the results found in this study. Moreover, the bacterium E. aerogenes has not yet been described in other studies as a causative agent of dermatopathy. Reptiles are considered reservoirs of important zoonotic microorganisms, such as P. aeruginosa, which can be transmitted by fecal contact, bites and wounds. However, the little information on P. aeruginosa in captive reptiles indicates the need for further studies to establish its zoonotic potential. A most adequate management conditions for the snake species could have decreased the severity of the lesions. The occurrence of P. aeruginosa and E. aerogenes found in this work may alert professionals for future clinical suspicions and adequate therapeutic management.