Climate-based risk models for Fasciola hepatica in Colombia.

A predictive Fasciola hepatica model, based on the growing degree day-water budget (GDD-WB) concept and the known biological requirements of the parasite, was developed within a geographical information system (GIS) in Colombia. Climate-based forecast index (CFI) values were calculated and represented in a national-scale, climate grid (18 x 18 km) using ArcGIS 9.3. A mask overlay was used to exclude unsuitable areas where mean annual temperature exceeded 25 °C, the upper threshold for development and propagation of the F. hepatica life cycle. The model was then validated and further developed by studies limited to one department in northwest Colombia. F. hepatica prevalence data was obtained from a 2008-2010 survey in 10 municipalities of 6,016 dairy cattle at 673 herd study sites, for which global positioning system coordinates were recorded. The CFI map results were compared to F. hepatica environmental risk models for the survey data points that had over 5% prevalence (231 of the 673 sites) at the 1 km2 scale using two independent approaches: (i) a GIS map query based on satellite data parameters including elevation, enhanced vegetation index and land surface temperature day-night difference; and (ii) an ecological niche model (MaxEnt), for which geographic point coordinates of F. hepatica survey farms were used with BioClim data as environmental variables to develop a probability map. The predicted risk pattern of both approaches was similar to that seen in the forecast index grid. The temporal risk, evaluated by the monthly CFIs and a daily GDD-WB forecast software for 2007 and 2008, revealed a major July-August to January transmission period with considerable inter-annual differences.

Morphological and molecular characterization of Neotropic Lymnaeidae (Gastropoda: Lymnaeoidea), vectors of fasciolosis.

Lymnaeidae play a crucial role in the transmission of fasciolosis, a disease of medical and veterinary importance. In the Neotropic, a region where fasciolosis is emergent, eight Lymnaeidae species are currently considered valid. However, our knowledge of the diversity of this taxon is hindered by the fact that lymnaeids exhibit extremely homogeneous anatomical traits. Because most species are difficult to identify using classic taxonomy, it is difficult to establish an epidemiological risk map of fasciolosis in the Neotropic. In this paper, we contribute to our understanding of the diversity of lymnaeids in this region of the world. We perform conchological, anatomical and DNA-based analyses (phylogeny and barcoding) of almost all species of Lymnaeidae inhabiting the Neotropic to compare the reliability of classic taxonomy and DNA-based approaches, and to delimitate species boundaries. Our results demonstrate that while morphological traits are unable to separate phenotypically similar species, DNA-based approaches unambiguously ascribe individuals to one species or another. We demonstrate that a taxon found in Colombia and Venezuela (Galba sp.) is closely related yet sufficiently divergent from Galba truncatula, G. humilis, G. cousini, G. cubensis, G. neotropica and G. viatrix to be considered as a different species. In addition, barcode results suggest that G. cubensis, G. neotropica and G. viatrix might be conspecifics. We conclude that conchological and anatomical characters are uninformative to identify closely related species of Lymnaeidae and that DNA-based approaches should be preferred.

Descripción morfológica de Cotylophoroncotylophorum (Digenea: Paramphistomidae) hallado enbovinos de Rionegro, Antioquia, Colombia / Descrição morfológica do Cotylophoron cotylophorum (Digenea: Paramphistomidae)em bovinos de Rionegro, Antioquia, Colômbia / Morphological description of Cotylophoron cotylophorum (Digenea: Paramphistomidae) in Cattle from Rionegro, Antioquia, Colombia

En Colombia se ha registrado la presencia de Paramphistomidae (Trematoda: Digenea) parasitandoel rumen de bovinos de la costa Caribe, los Llanos Orientales y el suroccidente. En estas publicacionesse menciona la presencia y prevalencia de los paramfistómidos, pero todas carecen de la descripciónmorfológica de los digeneos. El hallazgo de paramfistómidos adultos en el rumen de ejemplaresBos taurus, procedentes del sector Llanogrande, en el municipio de Rionegro, Antioquia, motivó lapresente investigación, con el propósito de describir los diferentes estadíos del parásito y establecerel estatus taxonómico específico. Del rumen de una hembra, Bos taurus, sacrificada en la CentralGanadera del municipio de Medellín, se extrajeron vivos 52 digeneos adultos. En el laboratoriose aislaron huevos que se incubaron hasta la obtención de miracidios. Con ellos se infectaron 50moluscos Lymnaea truncatula. La morfología de los adultos y estadíos larvarios del paramfistómidopermitió determinarlo como Cotylophoron cotylophorum. En L. truncatula se obtuvo una infeccióndel 5.1 %. Con este registro se amplia la distribución geográfica y altitudinal del parásito a la regiónaltoandina, noroccidental de Colombia.

The presence of Paramphistomidae parasites (Trematoda: Digenea) inside the rumen (first stomach) hasbeen recorded in Colombia in cattle from the Caribbean coast, the Eastern Plains region in the east, and thesouthwest of the country. However, studies on the presence and prevalence of the parasite do not include anymorphological description. This study includes research findings from adult Paramphistomidae parasitesin the rumen of Bos taurus specimens from Llanogrande in the municipality of Rionegro, Antioquia. Theaim of this research was to describe all the developmental stages of the parasite and to establish its specifictaxonomical status. 52 live adult parasites were found in the rumen of a female Bos taurus sacrificed inthe slaughter house Central Ganadera of Medellin. Eggs from adults were obtained in the laboratory, andhatching was stimulated to obtain miracidia. 50 Lymnaea truncatula snails were exposed to the miracidia,resulting in an infection rate of 5.1 %. The parasite was identified as Cotylophoron cotylophorum byusing adult morphology and larval stages. This finding expands the parasite’s geographical and altitudinaldistribution to the andean highlands in northwestern Colo.

Na Colômbia tem-se encontrado a presencia de Paramphistomidae (Trematoda: Digenea) parasitandono rúmen de bovinos da costa Caribe, os Llanos Orientales e no sul oeste. Nestas publicações tem-semencionado a presencia e prevalência dos paramfistómidos, mas todas carecem da descrição morfológicados digeneos. Do rúmen de uma fêmea Bos taurus proveniente do município de Rionegro e sacrificadana Central Ganadera do município de Medellín, se extraíram vivos 52 digeneos adultos. No laboratórioforam isolados os ovo e forma obtidos os miracidios. Com eles foram infetados 50 moluscos Lymnaeatruncatula. A morfologia dos adultos e estádios larvários do paramfistómido permitiu determinar-lho comoCotylophoron cotylophorum. Em L. truncatula foi obtido uma infecção de 5.1 %. Com este fato, se ampliaa distribuição geográfica e altitudinal do parasita na região alta dos Andes colombianos.

Aislamiento de Paramphistomidae en vacas de leche y en el hospedador intermediario (Lymnaea truncatula y Lymnaea columella) en una granja del trópico alto en el occidente de Colombia / Paramphistomidae isolation from dairy cows and its intermediate host (Lymnaea truncatula and Lymnaea columella) in a dairy farm in western Colombian high tropical region / Isolamento de Paramphistomidae em vacas leiteiras e no hospedeiro intermediário (Lymnaea truncatula y Lymnaea columella) numa fazenda do trópico alto no ocidente da Colômbia

Algunos Paramphistomidae (Trematoda: Digenea) parasitan el sistema digestivo de rumiantes de importancia económica en el mundo. En Colombia han sido reseñadas dos especies en bovinos de la costa Caribe y de los llanos orientales. Esta investigación tuvo como objetivo determinar la frecuencia de un paramfistómido en bovinos y caracoles de una hacienda localizada en Rionegro, Antioquia. En ésta se hicieron cuatro muestreos trimestrales entre julio de 2004 y julio de 2005. Se colectaron heces de los vacunos en ordeño para hacer diagnóstico mediante la técnica de Dennis. Los caracoles se capturaron en diversos ecosistemas acuáticos del lugar y su infección fue establecida mediante disección. Los huevos y los estadíos intramolusco del parásito fueron descritos y fotografiados. La frecuencia del paramfistómido fue del 100% en los 71 bovinos evaluados; de estos, el 80% (51 vacunos) presentaron además un fasciólido. Los huevos de ambos digeneos se diferenciaron mediante su coloración y la familia se confirmó mediante la eclosión de los miracidios. Se colectaron 1.146 caracoles determinados como Lymnaea truncatula y 335 determinados como Lymnaea columella, cuyas frecuencias de infección por el paramfistomido fueron 25, 47 y 1.79%, respectivamente. La morfología de los estadíos intramolusco obtenidos fue compatible con las familias Paramphistomidae y Fasciolidae. Este constituye el primer registro de un foco de paramfistomosis bovina en una zona alto andina, al occidente de Colombia, donde se destaca la presencia en simpatría con Fasciola hepatica y de dos especies de moluscos hospedadoras de ambos digéneos. Las frecuencias de infección en los caracoles, sugieren a L. truncatula como hospedador intermediario principal del paramfistómido y a L. columella como hospedador intermediario alterno del mismo...

Some Paramphistomidae (Region Trematoda: Digenea) parasitize the digestive system of economically important ruminants worldwide. Two species of these flukes have been recorded in cattle from the Caribbean Coast and eastern plains of Colombia. The objective of this study was to determine the frequency of paramphistomids in both dairy cattle (n = 71) and snails on a dairy farm in Rionegro (Antioquia), located in the western Andes. Four quarterly fecal samples were taken in the farm from July 2004 to July 2005. Faeces were collected from lactating dairy cows for diagnosis by using the Dennis technique. Snails were captured in diverse aquatic ecosystems of the locality and their infection status was confirmed by dissection under stereoscopic exam. The eggs and intra-mollusc stages of the parasite were described and photographed. The frequency of the paramphistomid was 100% in the 71 cows evaluated, of which 51 (80%) also presented fasciolid flukes. Eggs of the two digeneid species were differentiated based on their coloration, and the identity of the family confirmed through eclosion of the miracidia. In all 1146 snails were collected and identified as Lymnaea truncatula and a further 335 as L. columella, whose rates of infection to the paramphistomid were 25, 47 and 1.79% respectively. The morphologies of the intra-mollusc stages obtained were compatible with members of the families Paramphistomidae and Fasciolidae. This constitutes the first record of a focus of bovine paramphistomosis in the high Andean zone of western Colombia. The presence in sympatry of the paramphistomid with Fasciola hepatica is noteworthy, as is the finding of two host snail species for both digeneids. The frequencies of infection in the snails indicate that L. truncatula acts as the principal intermediate host of the paramphistomid and L. columella as its alternate intermediate host. Although the frequency of paramphistomids in the herd was very high, presence of the parasite was unsuspected until the present study...

Alguns Paramphistomidae (Trematoda: Digenea) parasitam o sistema digestivo de ruminantes de importância econômica no mundo. Na Colômbia têm sido identificadas duas espécies em bovinos da Costa Caribe e dos Llanos Orientais Nacionais. Este trabalho de pesquisa teve como objetivo determinar a freqüência de um paramfistómido em bovinos e caracóis de uma fazenda localizada em Rionegro, Antioquia. Nesta fazenda foram feitas quatro amostragens trimestrais entre julho de 2004 e julho de 2005 coletando fezes de bovinos em ordenho, para fazer o diagnóstico mediante a técnica de Dennis. Os caracóis foram capturados em diversos ecossistemas aquáticos do lugar e sua infecção estabelecida mediante dissecção. Os ovos e os estádios intramolusco do parasito foram descritos e fotografados. A freqüência do paramfistómido foi de 100% nos 71 bovinos avaliados, de estes, o 80% (51 bovinos) apresentaram ademais um fasciólido. Os ovos de ambos digêneos diferenciaram-se mediante sua coloração e a família se confirmou mediante a eclosão dos miracidios. Foram coletados 1.146 caracois catalogados como Lymnaea truncatula e 335 catalogados como Lymnaea columella, cujas freqüências de infeção pelo paramfistomido foram 25, 47 e 1.79%, respectivamente. A morfologia dos estádios intramolusco obtidos foi compatível com as familias Paramphistomidae e Fasciolidae. Isto constitui o primeiro registro de um foco de paramfistomosis bovina numa região alto andina, no ocidente da Colômbia, donde destaca-se a presença em simpatría com Fasciola hepatica e duas espécies de moluscos hospedeiros de ambos digêneos. As freqüências de infecção nos caracóis, sugerem L. truncatula como hospedeiro intermediário principal do paramfistómido e L. columella como hospedeiro intermediário alternativo do mesmo...

Modelling entomological-climatic interactions of Plasmodium falciparum malaria transmission in two Colombian endemic-regions: contributions to a National Malaria Early Warning System.

BACKGROUND: Malaria has recently re-emerged as a public health burden in Colombia. Although the problem seems to be climate-driven, there remain significant gaps of knowledge in the understanding of the complexity of malaria transmission, which have motivated attempts to develop a comprehensive model. METHODS: The mathematical tool was applied to represent Plasmodium falciparum malaria transmission in two endemic-areas. Entomological exogenous variables were estimated through field campaigns and laboratory experiments. Availability of breeding places was included towards representing fluctuations in vector densities. Diverse scenarios, sensitivity analyses and instabilities cases were considered during experimentation-validation process. RESULTS: Correlation coefficients and mean square errors between observed and modelled incidences reached 0.897-0.668 (P > 0.95) and 0.0002-0.0005, respectively. Temperature became the most relevant climatic parameter driving the final incidence. Accordingly, malaria outbreaks are possible during the favourable epochs following the onset of El Niño warm events. Sporogonic and gonotrophic cycles showed to be the entomological key-variables controlling the transmission potential of mosquitoes' population. Simulation results also showed that seasonality of vector density becomes an important factor towards understanding disease transmission. CONCLUSION: The model constitutes a promising tool to deepen the understanding of the multiple interactions related to malaria transmission conducive to outbreaks. In the foreseeable future it could be implemented as a tool to diagnose possible dynamical patterns of malaria incidence under several scenarios, as well as a decision-making tool for the early detection and control of outbreaks. The model will be also able to be merged with forecasts of El Niño events to provide a National Malaria Early Warning System.

Effect of the exposure to Fasciola hepatica (Trematoda: Digenea) on life history traits of Lymnaea cousini and Lymnaea columella (Gastropoda: Lymnaeidae).

The snails Lymnaea columella and Lymnaea cousini have both been reported as intermediate hosts of Fasciola hepatica in Colombia. The effect of the exposure to the parasite on survival, fecundity and size of these snails was evaluated by means of experimental infections and the life history traits of control and exposed groups were compared. Infection rates were 82.2 and 34% for L. columella and L. cousini, respectively. A reduction in fitness was observed in both species when exposed to the parasite: fecundity alone was reduced in L. columella whereas in L. cousini there was also a decline in survival rate. Unlike other studies, increased size was not observed in either species. On the contrary, a reduction in growth rate was observed in L. columella.

Morphological description and life cycle of Paragonimus sp. (Trematoda: Troglotrematidae): causal agent of human paragonimiasis in Colombia.

The first morphological description is made of all stages of the life cycle of a Paragonimus species infecting humans in Colombia. Larval stages were obtained both in vitro and from field collections. Adult Paragonimus spp. are described. The aquatic snail Aroapyrgus sp. serves as an intermediate host of this species, both naturally and experimentally, yielding rediae and cercariae. Crabs (Hypolobocera bouvieri monticola and H. emberarum) were found to be the natural second intermediate hosts, and individuals of another crab species (Strengeria sp.) were also infected in the laboratory.

Morphological and polymerase chain reaction-restriction fragment lenght polymorphism characterization of Biomphalaria kuhniana and Biomphalaria amazonica from Colombia.

In Colombia, five Biomphalaria planorbid species are known: B. kuhniana, B. straminea, B. peregrina, B. canonica and B. oligoza(var. B. philippiana). Among them, B. straminea is intermediate host of Schistosoma mansoni and B. peregrina has been found to be experimentally susceptible to this parasite. B. straminea is commonly confused with B. kuhniana and they have been clustered together with B. intermedia in the complex named B. straminea. The difficulties involved in the specific identification, based on morphological data, have motivated the use of new techniques as auxiliary tools in cases of inconclusive morphological identification of such planorbid. In the present study, five Biomphalaria populations from the Colombian Amazon region and from Interandian Valleys were morphologically identified and characterized by polymerase chain reaction-restriction fragment lenght polymorphism directed at the internal transcribed spacer region of the rRNA gene, followed by digestion of the generated fragment with restriction enzymes (DdeI, AluI, RsaI, MvaI and HaeIII). Known profiles of the Brazilian species B. straminea, B. peregrina, B. kuhniana, B. intermedia and B. amazonica, besides B. kuhniana from Colombia, were used for comparison. The five populations under study were morphologically and molecularly identified as B. kuhniana and B. amazonica.

Morphological and polymerase chain reaction-restriction fragment lenght polymorphism characterization of Biomphalaria kuhniana and Biomphalaria amazonica from Colombia

In Colombia, five Biomphalaria planorbid species are known: B. kuhniana, B. straminea, B. peregrina, B. canonica and B. oligoza(var. B. philippiana). Among them, B. straminea is intermediate host of Schistosoma mansoni and B. peregrina has been found to be experimentally susceptible to this parasite. B. straminea is commonly confused with B. kuhniana and they have been clustered together with B. intermedia in the complex named B. straminea. The difficulties involved in the specific identification, based on morphological data, have motivated the use of new techniques as auxiliary tools in cases of inconclusive morphological identification of such planorbid. In the present study, five Biomphalaria populations from the Colombian Amazon region and from Interandian Valleys were morphologically identified and characterized by polymerase chain reaction-restriction fragment lenght polymorphism directed at the internal transcribed spacer region of the rRNA gene, followed by digestion of the generated fragment with restriction enzymes (DdeI, AluI, RsaI, MvaI and HaeIII). Known profiles of the Brazilian species B. straminea, B. peregrina, B. kuhniana, B. intermedia and B. amazonica, besides B. kuhniana from Colombia, were used for comparison. The five populations under study were morphologically and molecularly identified as B. kuhniana and B. amazonica

Paragonimiasis: a view from Columbia.

Paragonimiasis is a zoonosis caused by adult trematodes of the Paragonimus genus. The infection in humans is a result of a complex transmission cycle that includes two obligate intermediate hosts, a snail and a crustacean or a crayfish, and a definitive mammalian host. It has been shown that 9 of the more than 40 species of Paragonimus described affect humans in over 39 countries in Asia, Africa and America. It is estimated that 20.7 million people have paragonimiasis and it is calculated that 195 million people are at risk of being infected. The illness usually is caused once the parasite has settled in the lung at the site of the main clinical symptoms: cough, thoracic pain and hemoptysis. The diagnosis of paragonimiasis is based on the patient's history, the parasitological findings (ova in sputum and in feces), and the result of radiological and immunological tests. In severe cases, the patient may suffer from life-threatening hemoptysis or pneumothorax. Currently, praziquantel is the drug of choice.