RESUMO
BACKGROUND: Snakebite envenoming is a neglected public health challenge that affects mostly economically deprived communities who inhabit tropical regions. In these regions, snakebite incidence data is not always reliable, and access to health care is scare and heterogeneous. Thus, addressing the problem of snakebite effectively requires an understanding of how spatial heterogeneity in snakebite is associated with human demographics and snakes' distribution. Here, we use a mathematical model to address the determinants of spatial heterogeneity in snakebite and we estimate snakebite incidence in a tropical country such as Costa Rica. METHODS AND FINDINGS: We combined a mathematical model that follows the law of mass action, where the incidence is proportional to the exposed human population and the venomous snake population, with a spatiotemporal dataset of snakebite incidence (Data from year 1990 to 2007 for 193 districts) in Costa Rica. This country harbors one of the most dangerous venomous snakes, which is the Terciopelo (Bothrops asper, Garman, 1884). We estimated B. asper distribution using a maximum entropy algorithm, and its abundance was estimated based on field data. Then, the model was adjusted to the data using a lineal regression with the reported incidence. We found a significant positive correlation (R2 = 0.66, p-value < 0.01) between our estimation and the reported incidence, suggesting the model has a good performance in estimating snakebite incidence. CONCLUSIONS: Our model underscores the importance of the synergistic effect of exposed population size and snake abundance on snakebite incidence. By combining information from venomous snakes' natural history with census data from rural populations, we were able to estimate snakebite incidence in Costa Rica. The model was able to fit the incidence data at fine administrative scale (district level), which is fundamental for the implementation and planning of management strategies oriented to reduce snakebite burden.
Assuntos
Bothrops/crescimento & desenvolvimento , Modelos Teóricos , Mordeduras de Serpentes/epidemiologia , Topografia Médica , Animais , Costa Rica/epidemiologia , Humanos , Incidência , Clima TropicalRESUMO
The use of conventional cytogenetic techniques in combination with fluorescent in situ hybridization (FISH) and single-nucleotide polymorphism (SNP) microarrays is necessary for the identification of cryptic rearrangements in the diagnosis of chromosomal syndromes. We report two siblings, a boy of 9 years and 9 months of age and his 7-years- and 5-month-old sister, with the classic Wolf-Hirschhorn syndrome (WHS) phenotype. Using high-resolution GTG- and NOR-banding karyotypes, as well as FISH analysis, we characterized a pure 4p deletion in both sibs and a balanced rearrangement in their father, consisting in an insertion of 4p material within a nucleolar organizing region of chromosome 15. Copy number variant (CNV) analysis using SNP arrays showed that both siblings have a similar size of 4p deletion (~6.5 Mb). Our results strongly support the need for conventional cytogenetic and FISH analysis, as well as high-density microarray mapping for the optimal characterization of the genetic imbalance in patients with WHS; parents must always be studied for recognizing cryptic balanced chromosomal rearrangements for an adequate genetic counseling.
Assuntos
Hibridização in Situ Fluorescente , Cariotipagem , Mutagênese Insercional , Polimorfismo de Nucleotídeo Único , Irmãos , Síndrome de Wolf-Hirschhorn/genética , Adulto , Criança , Deleção Cromossômica , Cromossomos Humanos Par 15/genética , Feminino , Humanos , Masculino , Síndrome de Wolf-Hirschhorn/patologiaRESUMO
Gamma irradiation on bovine serum and red blood cells (RBC) allows proliferation and growth of in vitro-cultured Babesia sp., and has potential application to inactivate contaminating viruses and bacteria from the substrate. Gamma irradiation with 25 kGy in a source of (60)Co was able to inactivate infectious bovine rinotracheitis (IBR) and bovine viral diarrhea (BVD) viruses in artificially contaminated serum; besides, bacteria were also eliminated. In vitro culture of Babesia bovis (B. bovis) in modified substrate, by adding irradiated serum with (60)Co at 25 kGy was propagated from 24-well culture plates to 225 cm(2) tissue culture flasks, and percentages of parasitized erythrocytes (PPE) from 2.4% to 8.8% were obtained. Infected RBC adapted to Irrad S were transferred to the irradiated substrate in vitro culture system, by using serum irradiated at 25 kGy and RBC from 10 to 70 Gy. The PPE ranged from 3.1 to 11. Culture of Babesia bigemina (B. bigemina) was established with Irrad S (25 kGy); its propagation was achieved in tissue culture flasks reaching PPE from 0.5 to 4.3 with no statistical difference (P > 0.05) when compared to the nonirradiated control culture (1.2-4.8). B. bigemina-infected RBCs were transferred to the modified culture system by adding irradiated serum and RBC (25 kGy and 70 Gy, respectively). PPE obtained in culture flasks were from 0.8 to 4.2. The results indicate that gamma irradiation is a suitable method to inactivate potential viral contamination and eliminate bacteria from bovine serum, to produce a live attenuated vaccine through the in vitro culture.
Assuntos
Babesia bovis/imunologia , Babesiose/veterinária , Doenças dos Bovinos/prevenção & controle , Eritrócitos/parasitologia , Eritrócitos/efeitos da radiação , Vacinas Protozoárias , Animais , Babesia bovis/efeitos da radiação , Babesiose/prevenção & controle , Bovinos , Criopreservação/veterinária , Relação Dose-Resposta à Radiação , Raios gama , Técnicas In Vitro , Masculino , Vacinas AtenuadasRESUMO
Bovine anaplasmosis presents a worldwide distribution. However, specific models for studying the epidemiology of the disease are not available. Epidemiological modeling encounters some difficulties due to a lack of culturing techniques for Anaplasma marginales, the causative agent, as well as for the lack of typing techniques to characterize strains. The chronic carrier state and the population dynamics of mechanical and biological vector also create difficulties. In addition, conventional serology and blood smear diagnostic techniques fail to detect all chronica carriers. Fortunately the needs for the accurate typing of isolates and for detecting chronica carriers made it possible to encourage the development of new tools based on molecular epidemiology principles. A. marginali isolates can now be typed by using panels of monoclonal antibodies, and the genes coding for some major surface proteins can be expressed or analyzed by looking at the nucleotide arrangement level. In the same manner, the latest techniques for detecting A. marginale chronic infections use DNA and RNA probes, and PCR-based methods to detect A. marginali DNA from bovine blood samples with extremely low rickettsaemias. Currently all these new epidemiological tools are being incroporated to experimental models to analyze their applicability for epidemiological studies in the near future
Assuntos
Anaplasmose/epidemiologia , Anticorpos Monoclonais/isolamento & purificação , Vetores de Doenças , Hibridização de Ácido Nucleico/fisiologia , Biologia Molecular , Rickettsia/isolamento & purificaçãoRESUMO
An epidemiological survey was conducted in south east Mexico, in an effort to establish the serological reactivity and carrier status to Babesia bigemina of an indigenous cattle population. The prevalance was obtained through the Indirect Fluorescent Antibody Test (IFAT), using an in vitro culture-derived B. bigemina antigen. A specific, digoxigenin-coupled, ~6kb B. bigemina-DNA probe (BBDP), was used to indicate the presence of the parasite. Serum samples from 925 animals of all ages, were obtained within the three regions (I, II, III) of the state of Yucatan and tested by IFAT. In addition, whole blood samples draw from 136 of the same animals of region II were analyzed using the BBDP. Positive IFAT (IFAT+) reactions were observed in 531 sera for a 57% overall prevalence. Regional values were: I = 157 + (56%), II = 266 + (68%) and III = 108 + (42%). Only 32 (23%) of the blood samples tested with BBDP showed distinctive hybridization signal, in contrast with 100 (73%) IFAT + animals. The responses distribution for IFAT vs. BBDP was: +/+ 23, +/- 77, -/+ 9 and -/- 27 respectively. It was found that the analytical sinsitivity of BBDP appears to be low for its utilization is widespread epidemiological surveys. It was considered, however, that the colorimetric probe mifht to be useful to safely detect transmission prone carriers, since it is able to detect parasitemias as low as 0.001
Assuntos
Babesiose/epidemiologia , DNA , FluorescênciaRESUMO
Diagnostico del Hidroarsenicismo cronico endemico y medidas preventivas a ser tomadas por las autoridades para evitar la alta incidencia de esta patologia en el territorio del Chaco, especialmente en las zonas aridas, carentes de rios
Assuntos
Humanos , Arsênio/intoxicação , Argentina , Doença CrônicaRESUMO
Diagnostico del Hidroarsenicismo cronico endemico y medidas preventivas a ser tomadas por las autoridades para evitar la alta incidencia de esta patologia en el territorio del Chaco, especialmente en las zonas aridas, carentes de rios
Assuntos
Humanos , Arsênio/intoxicação , Doença Crônica , ArgentinaRESUMO
Diagnostico del Hidroarsenicismo cronico endemico y medidas preventivas a ser tomadas por las autoridades para evitar la alta incidencia de esta patologia en el territorio del Chaco, especialmente en las zonas aridas, carentes de rios
Assuntos
Humanos , Arsênio/intoxicação , Doença CrônicaRESUMO
Diagnostico del Hidroarsenicismo cronico endemico y medidas preventivas a ser tomadas por las autoridades para evitar la alta incidencia de esta patologia en el territorio del Chaco, especialmente en las zonas aridas, carentes de rios