First report of Trypanosoma vivax infection in dairy cattle from Costa Rica.

An outbreak of haemoparasitoses occurred from October 2007 to July 2008 in cattle from the district of Rio Cuarto, province of Alajuela, Costa Rica. Fifty animals of various ages out of 450 Brown Swiss were affected. The animals presented fever, severe anemia, jaundice, abortion or premature birth, loss of appetite, decrease milk production and accentuated weight loss in a short period of time. Haemoparasites were observed in the blood smears: Anaplasma marginale was present in 17 animals (60.7%); Trypanosoma vivax in nine (32.1%) and Babesia bovis in two (7.1%). Three of the animals (10.7%) had a mixed infection with T. vivax and A. marginale. After treatment, all the animals were clinically recovered and subsequent blood samplings showed no parasites. Data suggest that the outbreak might be related to a decrease in the availability and quality of the pastures due to very heavy rainfalls during the year 2007, as well as an increase in the abundance of Boophilus microplus and Stomoxys calcitrans. This is the first report of the presence of T. vivax in Costa Rica.

Leptomonas costaricensis sp. n. (Kinetoplastea: Trypanosomatidae), a member of the novel phylogenetic group of insect trypanosomatids closely related to the genus Leishmania.

A flagellate isolated from the intestinal tract of a reduviid bug Ricolla simillima (Heteroptera) in Costa Rica was found to represent a new trypanosomatid species by the phylogenetic analysis of small subunit ribosomal RNA (SSU rRNA), glyceraldehyde phosphate dehydrogenase (GAPDH) and large subunit of RNA polymerase II (RPOIILS) genes. The phylogenetic position of this trypanosomatid, together with its typical promastigote morphology and the host identity, allowed its classification as a species that belongs to the polyphyletic genus Leptomonas. Interestingly, the new species was revealed as a member of the novel phylogenetic clade representing the closest known relative of Leishmania. With the new species used as an outgroup to root the Leishmania RPOIILS phylogenetic tree, the lineage of the Neotropical species L. enriettii was found to branch off early, and was followed by a deep split between the Old World and the remaining New World species. This tree topology supports the hypothesis that the initial transition to dixenous parasitism in this group pre-dated the continental split and that afterwards the Neotropical and the Old World groups evolved largely independently.

Effect of tacrolimus and partial hepatectomy on transthyretin metabolism in rats.

Liver transplantation, which serves as treatment of familial amyloidotic polyneuropathy (FAP), and domino liver transplantation, which utilizes resected livers from patients with FAP for treatment of liver diseases, may induce changes in transthyretin (TTR), a pathogenic FAP-related protein. To evaluate this possibility, we performed a 70% hepatectomy or administered tacrolimus to Dark Agouti (DA) rats for 7 days and then measured changes in liver TTR mRNA levels and changes in serum TTR concentrations. After hepatectomy, TTR mRNA levels decreased by 77%; at day 3, they returned to preoperative levels. Except for slightly elevated serum TTR concentrations 12 h after operation, serum TTR levels remained unchanged. Thus, partial hepatectomy did not influence serum TTR concentrations. After tacrolimus administration, TTR mRNA declined by 56% 12 h after the experiment started; however, after day 3, a rebound phenomenon occurred until day 7. Tacrolimus may facilitate serum TTR degradation, although production of TTR in the liver also increased. This finding -- that TTR, the source of FAP-inducing amyloid, did not increase after transplantation -- may help post-transplantation treatment of patients who have FAP and other liver diseases.

Trypanosomatid biodiversity in Costa Rica: genotyping of parasites from Heteroptera using the spliced leader RNA gene.

The biodiversity of insect trypanosomes is largely unknown, resulting in significant gaps in the understanding of pathogen evolution. A culture-independent preliminary survey of trypanosomatid fauna was conducted for the parasites of Heteroptera (Hemiptera) from several localities in Costa Rica. Trypanosomatid infections were detected by light microscopy of smeared gut contents. Out of 257 insects representing 6 families, infections were found in 62 cases; cultures were obtained for 29 new isolates. Gut material from infected hosts was preserved in the field using an SDS-EDTA buffer solution for subsequent DNA extraction in the laboratory. PCR amplification of the trypanosomatid-specific spliced leader (SL) RNA gene repeats was successful for 60 field samples. Eighteen distinct SL RNA typing units were identified in a set of 28 samples analysed in detail. Cluster analysis indicated that these typing units were unique and thus could represent new species and, in some cases, new genera. This study reveals only a minor fraction of the trypanosomatid biodiversity, which is anticipated to be high.

Entomological and ecological aspects of six sylvatic species of triatomines (Hemiptera, Reduviidae) from the collection of the National Biodiversity Institute of Costa Rica, Central America.

A total of 797 specimens of wild adult triatomines, belonging to six species from the entomological collections of the Costa Rican National Biodiversity Institute, was studied from the standpoint of their relative abundance, as reflected by light traps, distribution in the country, seasonal variations and climatic and altitudinal preferences. Triatoma dimidiata was the most abundant species (32.9% of the total specimens), with a very extensive distribution in different ecological zones, being more common between 100 to 400 m above sea level mainly at the end of the dry season. T. dispar was the third in frequency (21.5%), with narrower distribution, more abundant between 600 to 800 m and scarce during the dry season. Panstrongylus geniculatus and P. rufotuberculatus, second and fourth in frequency (22.1% and 15.1%, respectively), were widely distributed on both the Pacific and Caribbean basins, the former being more common between 80 to 270 m all year round and the latter below 800 m mainly during the first semester. Eratyrus cuspidatus which represented only 4.9% of the insects, was also present on both basins mainly below 200 m with a tendency to be scarce during certain months of the year, and was found in all types of ecological zones. Finally, Rhodnius pallescens, the least abundant species (3.6%) was restricted to very humid areas below 20 m, on the north side and Caribbean basin. With the exception of R. pallescens, males were more commonly found than females. Some epidemiological implications related to the six species are discussed.

Evidence of colonization of man-made ecotopes by Triatoma dimidiata (Latreille, 1811) in Costa Rica.

Triatoma dimidiata adults have been frequently found, during the last five years, in a dog kennel and a chicken coop, in the back yard of a well-built house, 15 km from San José, the capital of Costa Rica. In the chicken coop nymphs were also found. Two of the 11 dogs from the kennel were serologically positive for Trypanosoma cruzi infection. The inhabitants of the house, three adults and two children, were negative. This type of colonization by the insect, which is attracted to lights, is becoming common in old and new settlements, with different degrees of success, a fact with epidemiological implications and great relevance in the control strategies that can be applied.

Zymodeme and serodeme characterization of Leishmania isolates obtained from Costa Rican patients.

Thirty-four Leishmania isolates obtained from Costa Rican patients, from different geographical areas, were characterized by isoenzyme electrophoresis and indirect immunofluorescense with monoclonal antibodies. Thirty-two were characterized as L. panamensis strains and two were L. braziliensis variants. We confirm the evident predominance of L. panamensis as the main etiological agent of leishmaniasis in Costa Rica and the existence of L. braziliensis in the country.

[External morphology of Triatoma rickmani Zeledón & Ponce, 1972 seen under scanning electron microscopy]. / Morfologia externa de Triatoma ryckmani Zeledón & Ponce, 1972 vista através da microscopia electrônica de varredura.

A male of Triatoma ryckmani Zeledón & Ponce, 1972, was studied by scanning electron microscopy. Only few specimens of this species are known. In this paper, some structures from the head, thorax, abdomen and distal region of the second leg are shown. Some of them could have taxonomic importance, as the oculo-ocellar region, the buccula, the anterolateral angle of the collar, the scutellum with the process longer than the main body, the stridulatory sulcus with an unusual backward vermiform area, and the tibia-tarsal articulation, with a spongy fossula. The last structure was absent in specimens previously studied (Lent & Wygodzinsky 1979). Differences between this specimen and others previously described by several authors are discussed.

Comparison of the sex-pheromone components of Lutzomyia longipalpis (Diptera:Psychodidae) from areas of visceral and atypical cutaneous leishmaniasis in Honduras and Cost Rica.

The terpene components of extracts prepared from male Lutzomyia longipalpis (Diptera: Psychodidae) collected from four sites in Honduras and one in Costa Rica were analysed by high-performance liquid chromatography, gas chromatography and coupled gas chromatography--mass spectrometry. The terpene components of Lu. longipalpis from other regions of South America have previously been shown to be sex pheromones. The flies from the four areas of Honduras, where Leishmania chagasi infection may lead to visceral or atypical cutaneous leishmaniasis, were found to be homogenous, all producing 9-methylgermacrene-B. Three types of terpene (9-methylgermacrene-B, a novel homosesquiterpene and a small amount of diterpene) were detected in pools of flies from Liberia, Costa Rica, where only atypical cutaneous leishmaniasis has been found. These results indicate that there are probably at least two and possibly three distinct populations of Lu. longipalpis in this region. The clinical manifestation of Leishmania chagasi infection does not appear to be dependent on which population of Lu. longipalpis transmitted the parasite.

Molecular techniques in the characterization of Leishmania isolates from Central America.

The public-health problems caused by leishmaniasis in most countries in Central America are becoming more severe. This is partly because of the increasing size of the human populations that are at risk and their migratory patterns. Annual incidence of the disease in Costa Rica, Honduras, Guatemala, Panama and Nicaragua is estimated to be as high as 20,000 cases. Regional changes in the epidemiology of the various Leishmania spp. present have emphasized the need for innovative, sensitive and accurate diagnostic tools. PCR and isoenzyme, monoclonal antibody, schizodeme, DNA-probe and random-amplified, polymorphic DNA analyses have been tested. Preliminary indications that Leishmania chagasi was present in Costa Rica and Honduras and that interspecific hybrids occurred in Nicaragua have been confirmed using these methods. The distribution of the mexicana complex was also found to be broader and more heterogeneous than initially expected. Overall, there was 87% concordance between the results produced using the different techniques.

The characterization of Leishmania parasites and their vectors from Central America using molecular techniques.

The disfiguring cutaneous and mucocutaneous and often fatal visceral forms of leishmaniasis are an increasing public health problem in Central America. There are some evidences of a highest prevalence of L. braziliensis and L. mexicana in Guatemala; L. braziliensis, L. panamensis and L. infantum (L. chagasi) in Honduras and Nicaragua, and L. panamensis in Costa Rica and Panamá. Our research project, just starting, attempts to use molecular approaches for a more rapid and accurate diagnosis and to identify the parasites. The techniques include non-radioactive DNA probes, PCR, schizodeme, isoenzyme analysis and monoclonal antibodies; and specific recombinant peptides will be used to improve immunodiagnosis of the visceral form. Intra-specific heterogeneity in Leishmania isolates will be examined by pulsed field electrophoresis and random amplified polymorphic DNA. Using selected strains, the techniques will be compared on a regional basis leading to a better knowledge of parasite distribution and the related clinical entities. Furthermore, DNA probes for the identification of parasites in vectors and for sibling species of vectors, are also to be applied; chemical identification of sandfly male pheromones will be attempted possibly leading to potential novel control measures.

Leishmaniasis in the Caribbean Islands. A review.

A review is presented of the current knowledge relating to leishmaniasis in the West Indies. The only country where an autochthonous focus of cutaneous leishmaniasis has been discovered within the last 20 years is the Dominican Republic. Most of the cases are of the diffuse clinical type, which tend to be anergic to the Montenegro skin test, but subclinical or mild cases are apparently common. The responsible agent is a new species of Leishmania and the suspected vector is Lutzomyia cristophei, the only anthropophilic sandfly on the island; the black rat could be a wild reservoir for the parasite. Sporadic indigenous cases have also been reported in Martinique and in Trinidad. On the latter island, no new cases have been found in the last 60 years, and only an enzootic cycle between rodents and marsupials and Lu. flaviscutellata exists there at present; the responsible parasite in this cycle is L. amazonensis or a closely related species. An apparently indigenous case of visceral leishmaniasis has been reported in Guadeloupe but new studies are needed to confirm if this form of the disease is endemic on the island. The sandfly fauna in some of the larger islands is discussed in relation to the existence of possible vectors and the establishment of the disease. In the case of Haiti, there is no reason for human leishmaniasis not to be present as it is in the neighboring Dominican Republic. In Trinidad, the conditions are present for leishmaniasis to become a true zoonosis at any time, produced by L. amazonensis. In Cuba, conditions seem to be favorable for the introduction of cutaneous leishmaniasis in the near future. No predictions can be made at this time for other islands because of lack of information about the existence of the factors required.

Chagas' disease: risk factors for house infestation by Triatoma dimidiata, the major vector of Trypanosoma cruzi in Costa Rica.

The reduction of domiciliary infestation by insect vectors, the key to controlling Chagas' disease, depends on identification of housing features associated with infestation. In this study, log-linear modeling was used to reanalyze data collected in 1964-1968 from 371 houses on characteristics potentially associated with infestation by the vector Triatoma dimidiata in a Costa Rican town with endemic Chagas' disease. A possible increased risk of infestation was observed for houses with a dirt floor (as compared with houses with another floor type) and for houses in poor sanitary condition (as compared with houses in good sanitary condition). A new risk factor for house infestation, the presence of roof tiles, was identified; the odds of infestation for houses with a tile roof were 2.4 times greater than the odds for houses with a galvanized metal roof. This significantly increased risk is probably due to the harboring of T. dimidiata in stacks of spare tiles next to house walls rather than to the tile roofs themselves.

[Etiology of growth retardation (failure to thrive)]. / Etiología del retardo en el crecimiento (falla para progresar).

To determinate the different characteristics of growth and development that could categorize the etiology of failure to thrive (FTT), we analyzed 174 patients hospitalized because of FTT. Forty-eight percent had "organic and psychosocial" causes, and fifty-two percent had "non- organic" causes. The predominant organic factors were intrauterine retardation (41%) and gastrointestinal pathology (24%). Children with genetic and neurologic diseases were significantly more stunted and wasted than those of the "non-organic category (p less than 0.05). At discharge, the anthropometric data of the patients with genetic pathology remained with lower values than the ones observed in the other categories (p less than 0.05). The genetic and neurologic categories had the higher percentages of psychomotor retardation, and this impairment didn't improve after treatment. In all the categories, the motor areas were most retarded at the time of admission; nevertheless, they showed the higher percentage of recovery.

Morphological evidence by scanning electron microscopy of excretion of metacyclic forms of Trypanosoma cruzi in vector's urine.

Comparison by scanning electron microscopy (SEM) of Trypanosoma cruzi flagellates attached to the cuticle of the rectal gland of infected Dipetalogaster maxima nymphs, showed marked differences before and after feeding. Before feeding numerous metacyclic trypomastigotes were observed among the abundant epimastigotes that formed the carpet of flagellates. On the other hand, in insects that were allowed to urinate for 24 hours after a meal, the metacyclics were scarce, indicating that they had been detached by the urine flow. An asymmetric type of cell division, probably originating both an epi- and a trypomastigote, was occasionally observed. The occurrence of swellings at different levels of the flagella of epimastigotes suggests that secondary sites of attachment may be common.