Leishmania spp. epidemiology of canine leishmaniasis in the Yucatan Peninsula.

Canine Leishmaniasis is widespread in various Mexican states, where different species of Leishmania have been isolated from dogs. In the present study, we describe the detection of L. braziliensis, L. infantum, and L. mexicana in serum of dogs from the states of Yucatan and Quintana Roo in the Yucatan Peninsula (Mexico). A total of 412 sera were analyzed by ELISA using the total extract of the parasite and the iron superoxide dismutase excreted by different trypanosomatids as antigens. We found the prevalence of L. braziliensis to be 7.52%, L. infantum to be 6.07%, and L. mexicana to be 20.63%, in the dog population studied. The results obtained with ELISA using iron superoxide dismutase as the antigen were confirmed by western blot analysis with its greater sensitivity, and the agreement between the two techniques was very high.

Incrimination of the mosquito, Aedes taeniorhynchus, as the primary vector of heartworm, Dirofilaria immitis, in coastal Yucatan, Mexico.

Mosquito collections were carried out on microfilaraemic dogs, positive for Dirofilaria sp., for 18 consecutive nights in the coastal town of Celestún, Yucatan, southeast Mexico, during the rainy season (August) of 2007. A total of 292 female mosquitoes representing 12 species of dipteran Culicidae were collected: Anopheles albimanus (Wiedemann); Anopheles crucians (Wiedemann); Anopheles pseudopunctipennis (Theobald); Culex coronator (Dyar & Knab); Culex interrogator (Dyar & Knab); Culex nigripalpus (Theobald); Culex quinquefasciatus (Say); Culex salinarius (Coquillett); Aedes aegypti (Linnaeus); Aedes scapularis (Rondani); Aedes sollicitans (Walker), and Aedes taeniorhynchus (Wiedemann). Aedes taeniorhynchus and Cx. quinquefasciatus were the species found most commonly feeding on the dogs. Filarial nematodes were observed by microscopy in nine of the mosquito species collected; however, third-instar larvae were only observed in Ae. taeniorhynchus and An. crucians. Of 76 Ae. taeniorhynchus specimens found positive for Dirofilaria sp. by dissection, 14 were confirmed to be positive for Dirofilaria immitis (Leidy) by polymerase chain reaction (PCR). The resulting infection rate for D. immitis confirmed by PCR (6.2%) is higher than any infection rate for Ae. taeniorhynchus previously reported from the Americas.

Ochlerotatus taeniorhynchus: a probable vector of Dirofilaria immitis in coastal areas of Yucatan, Mexico.

Mosquito collections were done on microfilaremic dogs, positive for Dirofilaria immitis (Leidy), for 15 consecutive nights in Celestun, Yucatan, southeastern Mexico, during January 2007. In total, 275 mosquitoes (3 male and 272 female) of five species were collected: Ochlerotatus taeniorhynchus (Wiedemann), Ochlerotatus sollicitans (Walker), Culex quinquefasciatus Say, Culex interrogator (Dyar & Knab), and Aedes aegypti (L.). Oc. taeniorhynchus was the species most frequently collected, and it had the highest rate of feeding success and the highest attack rates. First (L1) and third (L3) instars of Dirofilaria were observed in all mosquito species collected except for Ae. aegypti: 23 of 223 Oc. taeniorhynchus, three of 40 Cx. quinquefasciatus, and one of six Oc. sollicitans and one of one Cx. interrogator were infected with Dirofilaria (10.3% of total examined mosquitoes). This is the first report of Dirofilaria (presumably D. immitis) isolation from wild-caught mosquitoes in Mexico. Results imply that D. immitis can develop from microfilaria to infective L3s in Oc. taeniorhynchus, Cx. quinquefasciatus, and Oc. sollicitans, but L3s (infectious) were only recovered in heads of Oc. taeniorhynchus. Thus, Oc. taeniorhynchus can be considered a potential vector of dirofilariasis in Celestun, because infective L3 Dirofilaria were found in the vicinity of the mouthparts, and this mosquito has a strong association with microfilaremic dogs in this study area.

Prevalence of the Dirofilaria immitis infection in dogs from Merida, Yucatan, Mexico.

The aim of the present study was to estimate the prevalence of Dirofilaria immitis infection, and to examine the relationship between host factors (gender, age and breed) and D. immitis infection in dogs. The study was designed as a cross-sectional study. A total of 676 dogs were examined for D. immitis infection. Adult worms (necropsy) and blood samples were collected from all animals for diagnosis of D. immitis. Blood samples were examined using a modified Knott's and thick drop techniques. Fifty-six of 676 dogs were diagnosed infected with D. immitis. The odds of infection were 2.85 times higher in female dogs, compared to male dogs (OR = 2.85, 95% CI = 1.5-5.5, P = 0.01). In addition, the odds of infection were 2.11 times higher in > or =3 years old dogs, compared with younger dogs (OR = 2.11, 95% CI = 1.1-4.2, P = 0.03). This information is important for a better understanding of the epidemiology of D. immitis in dogs in Yucatan, Mexico.

Chlorophyllin [CHLN] and the mutagenicity of monofunctional alkylating agents in Drosophila: the action of CHLN need not include an influence on metabolic activation.

The effect of chlorophyllin (CHLN) on the mutagenicity of four monofunctional alkylating agents (MFAAs) was evaluated in the wing spot test in Drosophila. Three of the compounds are direct-acting (ethylnitrosamine (ENU), methylnitrosourea (MNU), and methylmethanesulfonate (MMS)) and one indirect-acting (diethylnitrosamine, DEN). Results indicate that the mutagenicity of all four compounds is strongly inhibited by CHLN. The findings are not in agreement with the conclusion of Romert et al. (1992) that CHLN has no effect on the mutagenicity of direct acting MFFAs inferred from their work with MNU and ethylmethanesulfonate (EMS) in the V79 and Salmonella in vitro test systems. The results suggest the possibility that the action of CHLN need not include an inhibiting effect on metabolic activation.

The effect of treating Drosophila females with chlorophyllin on the yield of dominant lethals recovered from irradiated sperm.

Evidence is presented that treating the Drosophila female with chlorophyllin (CHLN) has a marked effect on the yield of dominant lethals induced by the irradiation of sperm. The yield is significantly greater in the embryonic period (between the egg and the first instar) and is significantly reduced in postembryonic stages compared with a sucrose control.

On the recovery of single spots with the flr phenotype in the wing spot test in Drosophila.

Graf et al. (U. Graf, F.E. Würgler, A.J. Katz, H. Frei, H. Juon, C.B. Hall, P.G. Kale, Somatic mutation and recombination test in Drosophila, Environment Mutagen. 6 (1984) 153-188.) described the overall results of assays of a series of compounds in the Drosophila wing spot test as indicating that single mwh spots appeared most frequently, followed by less frequent twin spots with both mwh and flr cells and lastly the 'quite rare' single flr spots. Data are presented below demonstrating that some compounds behave in a manner consistent with the above description, whereas others do not in that the frequency of single flr spots is equal to or exceeds that of twin spots and cannot be described as occurring 'rarely'. It is suggested that (large) flr singles be used as a measure of mutations/deletions directly from treated transheterozygotes. An argument is presented questioning the use of treated mwh +/+ TM3 individuals as an assay of mutations/deletions at the mwh+ locus.

[Prevalence of hepatitis B and C virus markers among medical staff at a third-level hospital]. / Prevalencia de marcadores de virus de hepatitis B y C en personal médico de un hospital de tercer nivel.

OBJECTIVE: To determine the prevalence of HBV and HCV serologic markers in serum samples of physicians working in "Hospital de Especialidades" of "Centro Medico Nacional de Occidente (HE-CMNO)". MATERIAL AND METHODS: The presence of hepatitis B surface antigen (HBsAg) and total hepatitis B core antibodies (HBcAc) were determined by hepanostika immunoassay, and anti-HCV by ELISA method (2nd. generation). RESULTS: Sixty-two physicians from medical or surgical services were included Fifty-one males (82%) and 11 females (18%). The participants mean age was 28 years (range 25-66) and their average length of practice was 8 years (range 2-44). Four physicians (6%) had a positive pattern of HBV serologic markers indicating post HBV infection. All of them were negative for HBsAg. One physician (2%) was positive for anti-HCV. The prevalence in physicians with multiple percutaneous injuries was 25%, for those in surgical services 14%, and 24% in physicians with more than 10 years of clinical practice. CONCLUSIONS: A higher prevalence of hepatitis virus infection was observed in medical doctors with more than 10 years of clinical activity working in surgical services and those suffering multiple percutaneous injuries.

Seroprevalence of antibodies against the excreted antigen superoxide dismutase by Trypanosoma cruzi in dogs from the Yucatan Peninsula (Mexico).

Numerous studies have shown the role of dogs as a reservoir for the American trypanosomiasis, as the bridge connecting sylvatic and peridomestic cycles. The objective of this study was to determine the prevalence of American trypanosomiasis in the dog population (630 sera) from seven localities in the Yucatan Peninsula (city of Mérida and the towns of Molas, Playa del Carmen, Akumal, Xcalacoop, Xcalac and Xahuachol). These data are key for developing control measures for the disease. The sera were analysed to detect antibodies against Trypanosoma cruzi, using Fe-SOD excreted as the antigenic fraction by ELISA and Western blot as confirmation. The total prevalence found in the Yucatan Peninsula was some 14.76%, with 10.74% in the state of Yucatan (city of Mérida, towns of Molas and Xcalacoop) and 21.34% in the state of Quintana Roo (towns of Playa del Carmen, Akumal, Xcalac and Xahuachol). However, a more thorough epidemiological study of the dog population, both wild and urban, in 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 neighbouring countries. These results again confirm that iron-superoxide dismutase excreted by T. cruzi constitutes a good source of antigen for serodiagnosis in epidemiological studies.

Evaluation of a Burdizzo castrator for neutering of dogs.

A Burdizzo castrator was evaluated for the neutering of dogs. Histological and morphological changes of spermatic cells and peripheral serum testosterone after challenge with a GnRH-analogue (gonadorelin) were assessed. There was a control group (G1), a surgically castrated group (G2) and a Burdizzo group (G3) divided in two, G3a receiving two crunches in each spermatic cord and G3b receiving one crunch in each spermatic cord. Sixteen days after application of the Burdizzo blood samples were taken from the dogs at 30 min interval during 2 h; after the second sample the dogs were treated with 1 mug/kg body weight of gonadorelin i.v. The same protocol of gonadorelin challenge was performed in G1 and G2 dogs. The G2 dogs were surgically castrated after the second blood sample, before the gonadorelin treatment, and the G1 dogs after the last blood sample. The excised gonads were examined histologically, and sperm smears were prepared from the caudae epididymidis. The testes and plexus pampiniformis of the G1 and G2 dogs had a normal histological appearance, and they had morphologically normal epididymal sperm cells. In all G3 dogs, there was an acute fibrosis with an inflammatory reaction in the plexus pampiniformis. The testes from the G3a dogs showed diffuse areas of infarction and degeneration of the parenchyma. Similar but less diffuse lesions were seen in group 3b dogs. The deferent ducts from all G3 dogs showed vasitis and/or sperm granulomas. Azoospermia or sperm malformations were observed in the epididymal smears from the G3 dogs. Testosterone concentration in the G1 dogs increased after gonadorelin application (p < 0.0001). The G2 dogs had basal testosterone levels after castration (p < 0.001) and did not respond to gonadorelin. Groups 3a and b showed a slight but non-significant increase in testosterone concentration after gonadorelin challenge, supposedly due to the reduction of testicular blood flow and loss of testicular interstitial tissue.

Sampling and analysis techniques for monitoring serum for trace elements.

We describe techniques for controlling contamination in the sampling and analysis of human serum for trace metals. The relatively simple procedures do not require clean-room conditions. The atomic absorption and atomic emission methods used have been applied in studying zinc, copper, chromium, manganese, molybdenum, selenium, and aluminum concentrations. Values obtained for a group of 16 normal subjects agree with the most reliable values reported in the literature, obtained by much more elaborate techniques. All of these metals can be measured in 3 to 4 mL of serum. The methods may prove especially useful in monitoring concentrations of essential trace elements in blood of patients being maintained on total parenteral nutrition.