Postoperative analgesic effects of either a constant rate infusion of fentanyl, lidocaine, ketamine, dexmedetomidine, or the combination lidocaine-ketamine-dexmedetomidine after ovariohysterectomy in dogs.

OBJECTIVE: To evaluate the postoperative analgesic effects of a constant rate infusion (CRI) of either fentanyl (FENT), lidocaine (LIDO), ketamine (KET), dexmedetomidine (DEX), or the combination lidocaine-ketamine-dexmedetomidine (LKD) in dogs. STUDY DESIGN: Randomized, prospective, blinded, clinical study. ANIMALS: Fifty-four dogs. METHODS: Anesthesia was induced with propofol and maintained with isoflurane. Treatments were intravenous (IV) administration of a bolus at start of anesthesia, followed by an IV CRI until the end of anesthesia, then a CRI at a decreased dose for a further 4 hours: CONTROL/BUT (butorphanol 0.4 mg kg(-1), infusion rate of saline 0.9% 2 mLkg(-1) hour(-1)); FENT (5 µg kg(-1), 10 µg kg(-1) hour(-1), then 2.5 µg kg(-1) hour(-1)); KET (1 mgkg(-1) , 40 µg kg(-1) minute(-1), then 10 µg kg(-1) minute(-1) ; LIDO (2 mg kg(-1), 100 µg kg(-1) minute(-1), then 25 µg kg(-1) minute(-1)); DEX (1 µgkg(-1), 3 µg kg(-1) hour(-1), then 1 µg kg(-1) hour(-1)); or a combination of LKD at the aforementioned doses. Postoperative analgesia was evaluated using the Glasgow composite pain scale, University of Melbourne pain scale, and numerical rating scale. Rescue analgesia was morphine and carprofen. Data were analyzed using Friedman or Kruskal-Wallis test with appropriate post-hoc testing (p < 0.05). RESULTS: Animals requiring rescue analgesia included CONTROL/BUT (n = 8), KET (n = 3), DEX (n = 2), and LIDO (n = 2); significantly higher in CONTROL/BUT than other groups. No dogs in LKD and FENT groups received rescue analgesia. CONTROL/BUT pain scores were significantly higher at 1 hour than FENT, DEX and LKD, but not than KET or LIDO. Fentanyl and LKD sedation scores were higher than CONTROL/BUT at 1 hour. CONCLUSIONS AND CLINICAL RELEVANCE: LKD and FENT resulted in adequate postoperative analgesia. LIDO, CONTROL/BUT, KET and DEX may not be effective for treatment of postoperative pain in dogs undergoing ovariohysterectomy.

Parasitic Zoonoses in Humans and Their Dogs from a Rural Community of Tropical Mexico.

A cross-sectional study was made on 89 inhabitants and their dogs from a rural community of Yucatan, Mexico, to determine the serological prevalence of some zoonotic parasitic agents. Samples were taken to monitor the presence and intensity of infection with gastrointestinal parasites in dogs. In humans, the serological prevalence of T. canis, T. gondii, and T. spiralis was 29.2%, 91.0%, and 6.7%, respectively. No associations were found between positive cases and studied variables. From the total of blood samples taken from dogs, 87 (97.6%) were seropositive to T. gondii; only 52 viable fecal samples were collected from dogs of which 46.2% had the presence of gastrointestinal parasites with low to moderate intensity; from those, 12% had the presence of T. canis. This study demonstrates the presence of the studied zoonotic agents in the area particularly T. gondii which suggest a common source of infection in dogs and humans and a high number of oocyts present in the environment. Preventive measures must be designed towards good prophylactic practices in domestic and backyard animals (T. canis and T. spiralis). Contaminated sources with T. gondii (food and water) should be further investigated in order to design effective control measures.

Evaluation of the isoflurane-sparing effects of fentanyl, lidocaine, ketamine, dexmedetomidine, or the combination lidocaine-ketamine-dexmedetomidine during ovariohysterectomy in dogs.

OBJECTIVE: To evaluate the isoflurane-sparing effects of an intravenous (IV) constant rate infusion (CRI) of fentanyl, lidocaine, ketamine, dexmedetomidine, or lidocaine-ketamine-dexmedetomidine (LKD) in dogs undergoing ovariohysterectomy. STUDY DESIGN: Randomized, prospective, blinded, clinical study. ANIMALS: Fifty four dogs. METHODS: Anesthesia was induced with propofol and maintained with isoflurane with one of the following IV treatments: butorphanol/saline (butorphanol 0.4 mg kg(-1), saline 0.9% CRI, CONTROL/BUT); fentanyl (5 µg kg(-1), 10 µg kg(-1) hour(-1), FENT); ketamine (1 mg kg(-1), 40 µg kg(-1) minute(-1), KET), lidocaine (2 mg kg(-1), 100 µg kg(-1) minute(-1), LIDO); dexmedetomidine (1 µg kg(-1), 3 µg kg(-1) hour(-1), DEX); or a LKD combination. Positive pressure ventilation maintained eucapnia. An anesthetist unaware of treatment and end-tidal isoflurane concentration (Fe'Iso) adjusted vaporizer settings to maintain surgical anesthetic depth. Cardiopulmonary variables and Fe'Iso concentrations were monitored. Data were analyzed using anova (p < 0.05). RESULTS: At most time points, heart rate (HR) was lower in FENT than in other groups, except for DEX and LKD. Mean arterial blood pressure (MAP) was lower in FENT and CONTROL/BUT than in DEX. Overall mean ± SD Fe'Iso and % reduced isoflurane requirements were 1.01 ± 0.31/41.6% (range, 0.75 ± 0.31/56.6% to 1.12 ± 0.80/35.3%, FENT), 1.37 ± 0.19/20.8% (1.23 ± 0.14/28.9% to 1.51 ± 0.22/12.7%, KET), 1.34 ± 0.19/22.5% (1.24 ± 0.19/28.3% to 1.44 ± 0.21/16.8%, LIDO), 1.30 ± 0.28/24.8% (1.16 ± 0.18/32.9% to 1.43 ± 0.32/17.3%, DEX), 0.95 ± 0.19/54.9% (0.7 ± 0.16/59.5% to 1.12 ± 0.16/35.3%, LKD) and 1.73 ± 0.18/0.0% (1.64 ± 0.21 to 1.82 ± 0.14, CONTROL/BUT) during surgery. FENT and LKD significantly reduced Fe'Iso. CONCLUSIONS AND CLINICAL RELEVANCE: At the doses administered, FENT and LKD had greater isoflurane-sparing effect than LIDO, KET or CONTROL/BUT, but not at all times. Low HR during FENT may limit improvement in MAP expected with reduced Fe'Iso.

Preventive and therapeutic DNA vaccination partially protect dogs against an infectious challenge with Trypanosoma cruzi.

American trypanosomiasis, or Chagas disease, is caused by Trypanosoma cruzi, and a vaccine would greatly improve disease control. While some studies in mice suggest that a vaccine is feasible, limited efficacy has been observed in dogs. We evaluated here the safety and efficacy of a DNA vaccine encoding TSA-1 and Tc24 antigens in a dog model of acute T. cruzi infection. Mongrel dogs were immunized with two doses of 500 µg of DNA vaccine, two weeks apart, and infected with T. cruzi (SylvioX10/4 strain) two weeks after the second vaccine dose. Another group of dogs was infected first and treated with the vaccine. Disease progression was monitored for up to 70 days post-infection. The vaccine did not induce any critical change in blood parameters, nor exacerbation of disease in vaccinated animals. On the contrary, it prevented anemia and a decrease in lymphocyte counts following T. cruzi infection in vaccinated dogs. Both preventive and therapeutic vaccination significantly reduced parasitemia, cardiac inflammation and cardiac parasite burden, and tended to reduce the development of cardiac arrhythmias. These results indicate that a preventive or therapeutic DNA vaccine encoding TSA-1 and Tc24 antigens is safe and may reduce both parasite transmission and the clinical progression of Chagas disease in vaccinated dogs. This DNA vaccine may thus be an excellent veterinary vaccine candidate. These data also further strengthen the feasibility of a Chagas disease vaccine for humans.

Evaluation of clinical and immunopathological features of different infective doses of Trypanosoma cruzi in dogs during the acute phase.

Infection with Trypanosoma cruzi is a major risk in Latin America, and dogs are believed to be good models for evaluating Chagas disease. Here, we evaluated the clinical and immunopathological alterations developed by mongrel dogs experimentally infected with different infective doses (2,000, 20,000, and 200,000 metacyclic trypomastigotes of Sylvio X10/4 strain kg(-1) via intraperitoneal). Clinical and electrocardiographic parameters, as well as antibody production and pathologic lesions were evaluated. All three doses of this strain of T. cruzi induced a similar pattern of infection characterized by cardiac arrhythmias and severe and diffuse myocarditis. Specific anti-T. cruzi IgG indicated seroconversion by day 14 after infection, and IgG levels increased during the period of evaluation. Mortality was observed only in dogs infected with the medium or high parasite doses, but not in the group infected with a low dose of 2,000 parasites kg(-1). Infection with a low dose of parasites provides an excellent nonlethal model to evaluate the immunopathology of the acute disease in dogs infected with the Sylvio X10/4 strain of T. cruzi.

Detection of different Leishmania spp. and Trypanosoma cruzi antibodies in cats from the Yucatan Peninsula (Mexico) using an iron superoxide dismutase excreted as antigen.

Although human leishmaniasis has been reported in 20 states in Mexico, no case of leishmaniasis has been reported in cats to date. In the Yucatan Peninsula, it has been found that dogs may act as reservoirs for at least three Leishmania species (Leishmania mexicana, Leishmania braziliensis, and Leishmania panamensis). In this study we identified specific antibodies against these three Leishmania spp. and Trypanosoma cruzi in the sera from 95 cats from two States on the Yucatan Peninsula, namely Quintana Roo and Yucatan, by ELISA and Western blot techniques using whole extract and an iron superoxide dismutase excreted by the parasites as antigens. As well as demonstrating the presence of trypanosomatid antibodies in the feline population on the Yucatan Peninsula, we were also able to confirm the high sensitivity and specificity of the iron superoxide dismutase antigen secreted by them, which may prove to be very useful in epidemiological studies.

Prevalence of antibodies against three species of Leishmania (L. mexicana, L. braziliensis, L. infantum) and possible associated factors in dogs from Mérida, Yucatán, Mexico.

Leishmania spp. has been recorded in humans and in dogs, and numerous studies have demonstrated that dogs act as reservoirs for visceral leishmaniasis. The objective of this study was to determine the prevalence of three species of the Leishmania genus and possible associated factors in sera of 218 dogs from two different populations in Mérida, Yucatán (Mexico). The sera were analyzed to detect antibodies against L. mexicana, L. braziliensis, and L. infantum using the superoxide dismutase- enzyme-linked immunosorbent assay (SOD-ELISA) and Western blot as confirmation. The Fe-SOD excreted was used as the antigenic fraction for the three Leishmania species. The prevalence values found were 30.2% (L. mexicana), 8.2% (L. braziliensis), and 11.9% (L. infantum), with L. mexicana seroprevalence being greater than L. braziliensis and L. infantum (p<0.05). Five percent (11/218) of the dogs showed antibodies against L. mexicana/L. braziliensis, 5.5% (12/218) with L. mexicana/L. infantum and 1.8% (4/218) with L. mexicana/L. braziliensis/L. infantum. No relationship (p>0.05) was found between antibodies against L. mexicana and breed, age, physical condition, or cutaneous lesions in dogs. This study provides evidence of antibodies against L. mexicana, L. braziliensis and L. infantum in dog populations from Mérida, Mexico.

An iron-superoxide dismutase antigen-based serological screening of dogs indicates their potential role in the transmission of cutaneous leishmaniasis and trypanosomiasis in Yucatan, Mexico.

An increasing number of studies have reported high infection rates for American cutaneous leishmaniasis in dogs, which have thus been proposed as the reservoir host. Canine leishmaniasis is widespread in different states in Mexico, where a number of Leishmania species have been isolated from dogs. In the present study, the detection of different Leishmania species is described in stray dogs from two localities, namely Tulum and Celestún on the Yucatan Peninsula (Mexico). The use of iron-superoxide dismutase excreted by the parasites as the antigen fraction and enzyme-linked immunosorbent assay and western blot tests allowed us to confirm the presence of at least three species of Leishmania (Le. mexicana, Le. braziliensis, and Le. panamensis), some of which are reported for the first time in this species. In addition to a high prevalence of Le. mexicana and Le. braziliensis, and to a lesser degree, Le. panamensis, there is a significant prevalence of Trypanosoma cruzi, suggesting that the dog may be a source of transmission of trypanosomiasis. However, a more thorough epidemiological study on the dog population, both wild as well as urban, of the Yucatan Peninsula will be required to design a control strategy for these diseases, paying particular attention to the population affected and even broadening the study to other Mexican states as well as neighboring countries. These results again confirm that iron-superoxide dismutase excreted by the different trypanosomatid species constitutes a good source of antigen for serodiagnosis in epidemiological studies.