Biological Strategies of Dermestes maculatus DeGeer (Coleoptera: Dermestidae) at Larval Stages in Different Temperatures.

The intraspecific variation in larval instars is a widely distributed phenomenon amongst holometabolous insects. Several factors can affect the number of instars, such as temperature, humidity, and density. Only a few references could be found in the literature because the invariability in the number of larval instars is considered normal, and the issue has raised little to no interest. Despite this, no study to date has intended to assess or focus on the larval development. Here, we analyzed the effect of different rearing temperature on the larval stage of Dermestes maculatus DeGeer (Coleoptera: Dermestidae). The results indicated that at all temperatures, L5 represented a decisive point for individuals as well as the other later larval instars, because the next step to follow was to pupate or molt to the next larval instar. Furthermore, there were mainly two populations, L5 and L6, although in different proportions according to temperature. We also found that at a greater number of instars, the larval development at all temperatures lasted longer. Moreover, the exponential model was the best adjustment in the developmental time of all populations as well as for the accumulated developmental time of L1-L4. Thus, we conclude that random factors such as genetics could probably cause interspecific variability in D. maculatus larval development.

Active Search on Carcasses versus Pitfall Traps: a Comparison of Sampling Methods.

The study of insect succession in cadavers and the classification of arthropods have mostly been done by placing a carcass in a cage, protected from vertebrate scavengers, which is then visited periodically. An alternative is to use specific traps. Few studies on carrion ecology and forensic entomology involving the carcasses of large vertebrates have employed pitfall traps. The aims of this study were to compare both sampling methods (active search on a carcass and pitfall trapping) for each coleopteran family, and to establish whether there is a discrepancy (underestimation and/or overestimation) in the presence of each family by either method. A great discrepancy was found for almost all families with some of them being more abundant in samples obtained through active search on carcasses and others in samples from traps, whereas two families did not show any bias towards a given sampling method. The fact that families may be underestimated or overestimated by the type of sampling technique highlights the importance of combining both methods, active search on carcasses and pitfall traps, in order to obtain more complete information on decomposition, carrion habitat and cadaveric families or species. Furthermore, a hypothesis advanced on the reasons for the underestimation by either sampling method showing biases towards certain families. Information about the sampling techniques indicating which would be more appropriate to detect or find a particular family is provided.

Cholinesterase activity during embryonic development in the blood-feeding bug Triatoma patagonica.

Triatoma patagonica Del Ponte (Hemiptera: Reduviidae), a vector of Chagas' disease, is widely distributed in Argentina and is found in sylvatic and peridomiciliary ecotopes, as well as occasionally in human dwellings after the chemical control of Triatoma infestans. Anti-cholinesteratic products can be applied in peridomiciliary areas and thus knowledge of cholinesterase activity during embryonic development in this species might contribute further information relevant to effective chemical control. Cholinesterase activity was characterized by reactions to eserine 10(-5) m, to increasing concentrations of substrate and to varying centrifugal speeds. Acetylcholinesterase activity was detected on day 4 and was significant from day 5. A reduction in cholinesterase activity towards acetylthiocholine (ATC) was observed on days 9 and 10 of development. Cholinesterase activity towards ATC and butyrylthiocholine (BTC) in homogenates of eggs was inhibited by eserine 10(-5) m. The shape of the curve indicating levels of inhibition at different concentrations of ATC was typical of acetylcholinesterase. Activity towards BTC did not appear to be inhibited by excess substrate, which parallels the behaviour of butyrylcholinesterases. Cholinesterase activity towards ATC was reduced in supernatant centrifuged at 15 000 g compared with supernatant centrifuged at 1100 g. The cholinesterase system that hydrolyzes mainly ATC seems to belong to the nervous system, as indicated by its behaviour towards the substrates assayed, its greater insolubility and the fact that it evolves parallel to the development of the nervous system. Knowledge of biochemical changes associated with the development and maturation of the nervous system during embryonic development would contribute to the better understanding of anti-cholinesteratic compounds with ovicidal action that might be used in control campaigns against vectors of Chagas' disease.

[Acanthamoeba sp. keratitis: first case confirmed by isolation and molecular typification in Bahía Blanca, Buenos Aires Province, Argentina]. / Queratitis por Acanthamoeba sp.: primer caso confirmado por aislamiento y tipificación molecular en Bahía Blanca, provincia de Buenos Aires, Argentina.

Some species of the Acanthamoeba genus cause keratitis, a very painful, most likely unilateral corneal infection , associated with eye and vision impairment. We here present a case of a 31-year-old female patient, a regular user of soft contact lenses without good practices of lens hygiene and handling. The patient attended medical consultation after two months of inflammation and pain in her right eye. After ophthalmological studies, and due to suspicion of a parasitic infection, a biopsy was performed and the sample submitted for bacteriological and parasitological analyses. Moreover, contact lens holders and lens cleaning solutions were studied. The samples yielded negative results for bacterial infection. However, cultivation of all samples showed the presence of amoeboid parasites. Isolated amoebae were morphologically and molecularly classified as members of the Acanthamoeba genus. This is the first case of keratitis caused by Acanthamoeba in Bahía Blanca, Buenos Aires Province, where the parasite was identified by specific and sensitive molecular techniques.

Human cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis in Santiago del Estero, Argentina: identification of parasites by monoclonal antibodies and isoenzymes

Estudos de diagnostico, caracterizacao parasitaria e identificacao foram conduzidos em pacientes humanos com lesoes cutaneas de leishmaniose na Provincia de Santiago del Estero, no norte da Argentina. Os procedimentos de diagnostico foram: biopsias de lesoes para utilizacao em esfregacos e inoculacao em hamster; aspiracao (com agulha) de ulceras, para cultura "in vitro". As tecnicas a IFAT-IgG e o teste intradermico de Montenegro. Oito cepas de parasitas foram isoladas, sendo estas obtidas de pacientes com lesoes ativas...

Human cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis in Santiago del Estero, Argentina: identification of parasites by monoclonal antibodies and isoenzymes.

Diagnostic and parasite characterization and identification studies were carried out in human patients with cutaneous leishmaniasis lesions in Santiago del Estero, Northern Province of Argentina. Diagnostic procedures were biopsies of lesions for smears and inoculations in hamster, needle aspirations of material from ulcers for "in vitro" cultures. Immunodiagnostic techniques applied were IFAT-IgG and Montenegro skin test. Primary isolation of eight stocks of leishmanial parasites was achieved from patients with active lesions. All stocks were biologically characterized by their behaviour in hamster, measurements of amastigote and promastigotes and growth "in vitro". Eight stocks were characterized and identified at species level by their reactivity to a cross-panel of sub-genus and species-specific Monoclonal Antibodies through an Indirect Immunofluorescence technique and a Dot-ELISA. We conclude from the serodeme analysis of Argentina stocks that: stocks MHOM/AR/92/SE-1; SE-2; SE-4; SE-8; SE-8-I; SE-30; SE-34 and SE-36 are Leishmania (Viannia) braziliensis. Three Leishmania stocks (SE-1; SE-2 and SE-30) did not react with one highly species-specific Monoclonal Antibody (Clone: B-18, Leishmania-(Viannia) braziliensis marker) disclosing two serodeme group patterns. Five out of eight soluble extracts of leishmanial promastigotes were electrophoresed on thin-layer starch gels and examined for the enzyme MPI, Mannose Phosphate Isomerase; MDH, Malate Dehydrogenase; 6PGD, 6 Phosphogluconate Dehydrogenase; NH, Nucleoside Hydrolase, 2-deoxyinosine as substrate; SOD, Superoxide Dismutase; GPI, Glucose Phosphate Isomerase and ES, Esterase. From the isoenzyme studies we concluded that stocks: MHOM/AR/92/SE-1; SE-2; SE-4; SE-8 and SE-8-I are isoenzymatically Leishmania (Viannia) braziliensis. We need to analyze more enzymes before assigning them to a braziliensis zymodeme.

Investigación de Entero y Ectoparasitosis en el área periférica de Bahía Blanca (República Argentina). Parte II / Research of Entero and Ectoparasitosis in the peripheral area of Bahía Blanca (Argentine Republic). Part II

Se estudiaron entero y ectoparásitos en cien niños de una villa periférica de la ciudad de Bahía Blanca (Área I) y enteroparásitos en ciencuenta niños de Patronato para niños huérfanos de esta ciudad (Área II) y de Guarderías o Jardines maternales (Área III) de la zona céntrica de la ciudad. Los resultados señalan que en el área periférica (Área I), se observa un aumento en la prevalencia parasitaria no solo respecto de las Áreas I y II, sino también respecto de que los autores hallaron en la parte I del presente trabajo. Se continúa hallando un elevado poliparasitismo y se demuestra que las condiciones de buena vivienda, comida y vestimenta adecuada no permiten por sí mismas erradicar las enteroparasitosis, sino que se hace necesario una adecuada y permanente educación sanitaria, bien dirigida e intensiva para lograr el objetivo deseado de disminuir la incidencia de las enteroparasitosis en la ciudad de Bahía Blanca.