[Housedust mites in Punta Arenas city, Chile]. / Acaros del polvo de habitaciones en la ciudad de Punta Arenas, Chile.

In medicine, the importance of mites in house dust gains importance from day to day. The close relation between these arthropods and man is the cause of a series of health problems such as allergic asthma, rhinitis and/or dermatitis. House dust samples were collected between January and December 1991 in Punta Arenas, city, Chile. Samples were processed by the Artigas and Casanueva (1983) technique, modified by Muñoz et al. (1983). The isolated specimens were subsequently identified using the Artigas and Casnueva (1983) pictorial key. Of the 134 samples study, 29.1% presented one or more mite species. A total of 13 species were classified. Eight of them were registered for the city of Punta Arenas for the first time. Average weight of the dust analysed was 8.4 g. Mites were found from 0.2 g. onwards. A total of 1768 specimens was collected. The species more representative were: Blomia tjibodas (30.1%), Glycyphagus destructor (22.5%) and Tyrophagus putrescentiae (10.8%). The seasons that presented the higher proportions of mites were autumn (39.4%) and spring (37.1%).

Diplostomatid metacercariae in the brain of silversides from Lake Riñihue, Chile.

The tissue locations and effects produced by metacercariae of Diplostomum (Austrodiplostomum) mordax and Tylodelphys destructor in the brain of 30 silversides (Basilichthys australis) from Lake Riñihue in Chile, were evaluated. Metacercariae were mainly observed in the interlobular infoldings, meninges and ventricles of the brain. The prevalence was 18 (60%) and the intensities were usually low (1 to 9 metacercariae), with no inflammation or invasion of the parenchyma, except for one fish which had 130 parasites associated with a moderate inflammatory reaction. Asymmetry in the distribution of metacercariae in the cerebral hemispheres was observed in one (3%) of the 30 fish.

[Seasonal infection by metacercaria of Diplostomum (Austrodiplostomum) mordax (Szidat and Nani, 1951) and Tylodelphys destructor Szidat and Nani, 1951 in the Chilean Silverside, Basilichthys australis Eigenmann, 1927 (Pisces:Atherinidae) in Lake Riñihue]. / Infección estacional por metacercarias de Diplostomum (Austrodiplostomum) mordax (Szidat y Nani, 1951) y Tylodelphys destructor Szidat y Nani, 1951 en el pejerrey chileno, Basilichthys australis Elgenmann, 1927 (Pisces:Atherinidae) en el lago Riñihue, Chile.

Between 1993 and 1994, 129 specimens of Basilichthys australis from Lake Riñihue (39 degrees 50 minutes S; 72 degrees 20 minutes W) in the south of Chile were examined, in order to determine the prevalence and mean intensity of infections by Diplostomum mordax and Tylodelphys destructor metacercariae in the brain of fishes. Prevalence and mean intensity of D. mordax and mean intensity of T. destructor not showed seasonal significant differences. Prevalence of T. destructor was higher in summer than in winter, spring and autumn. No association between intensity of infection by D. mordax and T. destructor and body condition of the host was observed.

[Prevalence of protozoa infections in synanthropic rodents in Valdivia City, Chile]. / Prevalencia de infección por protozoos en roedores sinantrópicos de la ciudad de Valdivia, Chile.

In order to determine the prevalence of infection by blood and intestinal protozoa in 57 synanthropic rodents from Valdivia city, a study was carried out in the period march-september 1986. The group of rodents studied was constituted by 31 Mus musculus, 19 Rattus rattus and 7 Oryzomys longicaudattus, being 42 males and 15 females. Diagnostic forms of protozoa were found in 70.2% of the investigated animals. The presence of five species of enteroprotozoa and one species of hemoflagelate was detected. The number and the corresponding percentages of infected animals were the following: Giardia muris, 21 (36.8%), Hexamita muris, 22 (38.6%), Trichomonas muris, 27 (47.4%), Entamoeba muris 9 (15.8%), Eimeria sp. 15 (26.3%) and Trypanosoma lewisi 9 (15.8%). Not significant differences were observed when considering host or sex of the species found infected. Furthermore, the yielding of fecal examination considering direct examination, sugar solution flotation and SAFS were compared. The sugar solution flotation technique showed the highest percentage diagnosis of coccidia, whereas SAFS was more efficient for detecting G. muris and E. muris.

[Intestinal geohelminthosis in man and domestic animals in the riverside sections of the Valdivia River Basin, Chile]. / Geohelmintosis intestinales en el hombre y animales domésticos de sectores ribereños de la cuenca del río Valdivia, Chile.

In March-October 1987 were analyzed 1295 coprological specimens in a sample of the human population who lives in riverside localities in the Valdivia River Basin, Chile. A 23.6% of examined persons presented infection by one or more helminth species. The prevalence of infection by Ascaris lumbricoides, Trichuris trichiura and Trichostrongylidae gen. sp. were 15.5, 12.7 and 0.2%, respectively. The prevalence of human ascariosis and trichuriosis were greater in pre-school and school children. The sex of the host and prevalence of geohelminthosis did not show any relationship. Prevalences of ascariosis and trichuriosis were higher in persons from houses with no sanitary fecal and water disposal. Over 35% and 20.7% of family groups showed infection by A. lumbricoides and T. trichiura, respectively in over 40% of the members of each group. Fecal samples from domestic mammals revealed the following prevalences rates for helminth infections: in dogs 19.0 and 15.2% for Toxocara canis and Uncinaria stenocephala respectively, in cats 65.1% for Toxocara cati, and in pigs 25.4 and 3.2% for Ascaris suum and Trichuris suis respectively. Some of these species are clearly demonstrated agents of zoonoses.

[Housedust mites++ in the city of Valdivia, Chile]. / Acaros del polvo de habitaciones de la ciudad de Valdivia, Chile.

In the house dust there are different species of mites, which have medical importance because they are related to allergic asthma, rhinitis and/or dermatitis. Between april-august 1989 and march-june 1990, 100 samples of house dust collected in the city of Valdivia, Chile were analyzed. By using special techniques the samples were examined and classified. In the present research 70 samples of dust were positive, which showed one or more species of mites. Thirteen species and one genus were classified. The average quantity of house dust examined by sample was 0.69 g and a total of 701 mites were isolated, being identified 691 of them: Glycyphagus destructor (23.4%), G. domesticus (22.7%), Blomia tjibodas (19.2%), Cheyletus eruditus (6.5%) and Chortoglyphus arcuatus (12.0%), were the most frequent species found. In 74.2% of the positive samples two or more species of mites were observed, being the most common the association of two species, with the combinations: G. destructor-G. domesticus; G. domesticus-Tyrophagus putrescentiae; G. destructor-Ch. eruditus.

[New records of human diphyllobothriasis in Chile (1981-1992), with a case of multiple Diphyllobothrium latum infection]. / Registro de nuevos casos de difilobotriasis humana en Chile (1981-1992), incluido un caso de infección múltiple por Diphyllobothrium latum.

Fifteen new human cases of diphyllobothriasis in Chile are reported, one of them a multiple case of infection by Diphyllobothrium latum. Five scolices and 28 m of strobila were recovered after treatment with Niclosamide in a male adult patient with multiple infection. In other 5 cases, after treatment, only one worm was recovered in each person and all corresponded to D. latum species; worms measured between 2.9 to 11.0m. In 9 cases, only the eggs of parasites were reported in the coprological exam. Thirteen cases were determined in the lakes area from south of Chile where infection by plerocercoids in salmonids is very frequent and the persons consume smoked and raw ("cebiche") fishes.

[Blastocystosis and other intestinal protozoan infections in human riverside communities of the Valdivia River basin, Chile]. / Blastocistosis y otras infecciones por protozoos intestinales en comunidades humanas ribereñas de la cuenca del Río Valdivia, Chile.

Between March and October 1987, the prevalence of infection by Blastocystis hominis and other intestinal protozoan, their relationship with the age and sex of the hosts, and the percentage of infected persons in family groups were determined in riverside communities of Valdivia River Basin, Chile. One or more intestinal protozoan species were determined in 72.5% of the examined persons. The prevalence was greater for B. hominis (61.8%). The prevalences of B. hominis, Endolimax nana and Entamoeba coli were greater in relation to the age of the host. The sex of the host and prevalence of infections by B. hominis and other species of intestinal protozoans did not show association. Prevalence of B. hominis was greater in persons from houses with no sanitary faeces disposal. Over 60% of the members of family groups showed infection by B. hominis in 53.1% of the groups compared to 2.4%-21.8% of infections by other protozoan species. Faecal samples of 45 pigs revealed 22.2% of infection by Blastocystis.

[Histopathology of Kingiella chilenica (bivalvia, cyamiidae) parasitized by rediae and cercariae of the Gymnophallidae family]. / Histopatología de Kingiella chilenica (Bivalvia, Cyamiidae) parasitada por redias y cercarias de la familia Gymnophallidae.

Gonadal and digestive gland tissues of Kingiella chilenica specimens, which were infected with trematode larvae, were examined to determine the organs that are normally invaded by these parasites. Rediae containing cercariae of this digenetic trematod, appeared exclusively restricted to the tissues of the digestive gland. Consequently, no damage or alterations were observed in the gonad or other related tissues of the infected specimens. This, linked to the fact that parasitized females may also appear with brooded embryos, supports the conclusion that the reproductive activities of the bivalve mollusc are not affected by the presence of these infecting larvae.

[Larval stages of digenea in Kingiella chilenica (Mollusca-Bivalvia, Cyamiidae]. / Estados lavales de digenea en Kingiella chilenica (Mollusca-Bivalvia, Cyamiidae).

The presence of rediae and cercariae of the Gymnophalidae family, in the Cyamiidae bivalve, Kingiella chilenica is reported. A general morphological description of the reported cercariae is given.

[Distribution of the infection by Camallanus corderoi (Nemata: Spiruroidea) in different autochthonous hosts and localities of the Valdivia river basin, Chile]. / Distribución de la infección por Camallanus corderoi (Nemata: Spiruroidea) en distintos hospedadores autóctonos y sectores de la cuenca del río Valdivia, Chile.

Six hundred and thirty nine autochthonous fish were examined in 1986-1987 in search for Camallanus corderoi infection on different biotopes from Valdivia River basin (between 39 degrees 30'-40 degrees 00'S, 73 degrees 30'-71 degrees 45'' W). Brachigalaxias bullocki, Galaxias maculatus, Galaxias platei, Aplochiton taeniatus, Cheirodon australe, Basilichthys australis and Cauque mauleanum are new hosts for C. corderoi. Infection by C. corderoi in fish is acquired by ingestion of infected copepods and prevalence and intensity of infection showed differences between host fish and biotopes. In general, infrapopulations of C. corderoi showed overdispersion in different hosts.

[Trichomonas vaginalis infection in pregnant women and newborn infants]. / Trichomonas vaginalis en embarazadas y en recién nacidos.

We studied 149 pregnant women at delivery and 113 newborns in order to determine the frequency of T vaginalis infection. Neutral red stain, dark field microscopy and culture methods were used with comparable yields. The age of women ranged from 12 to 43 years. A 27.5% infection rate was detected in mothers but all newborns were free from infection. Infection rates in relation to age among mothers confirmed previously reports.

[Epidemiology of diphyllobothriasis in the Valdivia river basin, Chile]. / Epidemiología de la difilobotriasis en la cuenca del Río Valdivia, Chile.

In the Valdivia (Chile) river basin 1,295 inhabitants of 6 riverside districts were examined between March and October 1987 and showed a 1.2% of prevalence by Diphyllobothrium in the districts of Riñihue and Las Huellas. Prevalence of 5.3% and 9.8% respectively were registered in dogs of the districts of Riñihue and Malihue. No cat or pig infection was observed in the different districts. The parasites recovered after the treatment were identified as Diphyllobothrium latum. Human infection by D. latum in the districts affected results from the consumption of smoked or insufficiently cooked fish. The investigation of 1,450 fish (4 exotic species and 11 autochthonous ones), caught in the Valdivia river basin in 1986 and 1987, showed the existence of plerocercoids of D. latum and/or Diphyllobothrium dendriticum in Salmo gairdneri and Salmo trutta among exotic fish and in some autochthonous species. Prevalence and mean intensity in the infection of fish as well as the degree of aggregation in the infrapopulations varied in the different districts. Some species of fish would act as intermediary hosts and others as paratenic hosts in the life cycles of Diphyllobothrium spp. in the Valdivia river basin. An improvement in the conditions of basic sanitation, in sanitary education and in the treatment of infected persons is proposed as a means for the control of diphyllobothriasis in the districts affected.

[New hosts for Helicometrina nimia Linton, 1910 (Digenea: Opecoelidae) in the south-center coast of Chile]. / Nuevos hospedadores para Helicometrina nimia Linton, 1910 (Digenea: Opecoelidae) en la costa centro sur de Chile.

Two new hosts (Calliclinus geniguttatus and Calliclinus nudiventris) for Helicometrina nimia are reported from Chile. Comments concerning geographical distribution of H. nimia and diet of marine fish hosts are given.