A new species of Leptotrombidium (Acari:Trombiculidae) collected in active rice fields in northern Thailand

Leptotrombidium (Leptotrombidium) chiangraiensis Tanskul & Linthicum is described and illustrated as new from specimens collected from the rodents Rattus rattus (L., 1758), Rattus argentiventer (Robinson & Kloss, 1916), Rattus losea (Swinhoe, 1870), and Bandicota indica (Bechstein, 1800) in Chiangrai Province northern Thailand. The new species was collected in active rice fields and adjacent fruit plantation areas. The etiological agent of scrub typhus, Orientia (formerly Rickettsia) tsutsugamushi (Hayashi), has been isolated from patients who live and work in the same habitat where L. chiangraiensis is the predominant Leptotrombidium species.     

A new ecology for scrub typhus associated with a focus of antibiotic resistance in rice farmers in Thailand

Following the documentation of chloramphenicol-resistant and doxycycline-resistant strains of Orientia tsutsugamushi (Hyashi) in northern Thailand, we conducted ecological and epidemiological studies near the houses of patients hospitalized with antibiotic-resistant infections. New associations between chiggers, rodents, and O. tsutsugamushi in active rice agriculture areas, an ecological habitat not described previously, are reported. Rattus rattus (L.) was the most common species (representing 85.8% of the 1,433 rodents processed), followed by Rattus losea (Swinhoe) (9.4%), Bandicota indica (Bechstein) (3.6%), and Rattus argentiventer (Robinson and Kloss) (1.3%). O. tsutsugamushi was isolated from 30% of the R. rattus and R. losea, 29% of the B. indica, and 33% of the R. argentiventer collected. Mean minimum infection rates were 0.03 in Leptotrombidium chiangraiensis Tanskul & Linthicum, a new species of chigger, and 0.002 in Leptotrombidium imphalum (Vercammen-Grandjean & Langston), a chigger species not previously associated with scrub typhus transmission. Efficient vertical and horizontal transmission of O. tsutsugamushi by L. chiangraiensis and L. imphalum was demonstrated. During a 19-mo period from October 1993 to April 1995, the overall prevalence of human IgM and IgG antibody to O. tsutsugamushi was 25.5 and 47.3%, respectively. L. chiangraiensis and L. imphalum are incriminated as vectors of O. tsutsugamushi in a rice field habitat associated with a focus of antibiotic resistance.     

Investigation of the life cycle and adult morphology of the avian blood fluke Austrobilharzia variglandis (Trematoda: Schistosomatidae) from Connecticut

This study was undertaken to expand the current knowledge of the life cycle and adult morphology of the avian schistosome Austrobilharzia variglandis, which causes a marine cercarial dermatitis in New England. The specific objectives were to: (1) investigate the seasonality of the infection in the molluscan intermediate host, Ilyanassa obsoleta; (2) determine which bird species are acting as natural definitive hosts for the parasite; and (3) characterize the morphology of the parasite using scanning electron microscopy (SEM). One-thousand individuals of I. obsoleta were collected each month for 14 consecutive months and examined for the parasite. Ten to 15 specimens of each of the following avian species, Larus argentatus, Larus delawarensis, Larus marinus, Phalacrocorax auritus, and Branta canadensis, and 2 individuals of Larus atrilla, were collected and examined for schistosomes. Twenty adult male and 10 adult female specimens of A. variglandis were processed for SEM. Ilyanassa obsoleta was found to maintain a relatively low prevalence of infection (0.7-5.1%) throughout the 14-mo study, but no fully developed cercaria were visible in sporocysts recovered from snails collected in winter months. The Larus species had both the highest prevalence (85-92.8%) and highest mean intensity (12.1-34.5 male worms) of infection with A. variglandis. These data suggest that overwintering snail populations can harbor viable infections and in the spring infect shore birds (or humans) with cercaria. The snail and definitive host data suggest that A. variglandis is a year-round resident of the state.(ABSTRACT TRUNCATED AT 250 WORDS)     

Natural Babesia infection sought in black and Norway rats trapped in five Egyptian Governorates

Babesiosis is a protozoal disease caused by members of the genus Babesia transmitted by the ixodid ticks. It is a parasite of various mammalian hosts as bovine (B. bovis), equine (B. equi), rodent (B. microti), canine (B. canis) and others. Human cases of babesiosis have been reported from several countries including Egypt. It is now well established that man may become infected (Fulminating or Subclinical) with several species of Babesia without prior splenectomy. In this paper, a total of 398 Rattus rattus and 90 R. norvegicus were trapped in Suez, Ismailia, Port Said, North Sinai and South Sinai Governorates. Blood films were taken from the atil after a simple cut of its end. The films were fixed in acetone free methyl alcohol and stained with Giemsa stain as usual. The results showed that all rats trapped in Ismailia had Babesia infection, then decreased in North Sinai, Port Said, South Sinai and was zero in Suez. As double infection. Trypanosoma lewisi was found in rats trapped in Port Said, North Sinai and South Sinai. But none had Theileria infection. The medical and veterinary importance of these results were discussed.     

Spatial Distribution of Ions in Groundwater under Agricultural Land

This study investigated the characteristics of shallow groundwater quality under agricultural areas dominated by rice paddy fields, vegetable fields, and a residential zone on an alluvial basin by examining spatial distributions of Cl?, Na+, NO3?, and SO42? concentrations. Seasonal changes in spatial distribution of ion concentrations during one cultivation period and the causes of the changes were discussed. Changes in spatial distribution of Cl? and Na+ concentrations of the groundwater were mainly affected by seasonal changes in precipitation concentrations. NO3? concentration was strongly influenced by fertilization of vegetable fields and a following heavy rainfall. Elevated NO3? concentration was less likely to occur under paddy fields than under vegetable fields. It was suggested that paddy fields might mitigate NO3? contamination of shallow groundwater possibly because of denitrification in paddy soil in an anaerobic state during ponding. As for SO42?, it was acknowledged that there could be a specific point source near a particular observation well.     

Ixodid ticks infesting rodents and sheep in diverse biotopes of southern India

A total of 127 rodents were trapped in southern India. Examination of these rodents revealed the presence of 2 species of ticks, Haemaphysalis spinigera and Rhipicephalus ramachandrai. The former species is the principal vector of Kyasanur Forest Disease (KFD) in India, and the latter's role, if any, is unknown. Sheep grazing in 1 of the study area were infested with another ixodid tick. Haemaphysalis intermedia, which is a vector of Bhanja virus in India. The presence of H. spinigera on domestic rats is important from the standpoint of KFD enzootiology. This tick shows a narrow habitat preference but a wide host range. In peridomestic situations, the field rodent Bandicota bengalensis did not harbor any tick species. Contiguity of feral and domestic biotopes in some areas contributed to the transfer of R. ramachandrai from its preferred wild rodent host, Tatera indica, to domestic rats Rattus sp.     

Dermatologic manifestations of Schistosomiasis mansoni

Schistosomiasis mansoni, a potentially severe disease that victimizes an appreciable number of US citizens in this hemisphere, shows cutaneous changes corresponding to various stages in the life cycle of the causative parasite within its definitive host. A transient pruritus or dermatitis, probably irritative, characterizes the stage of cercarial penetration. Urticaria, periorbital edema, and rarely a purpuric eruption may occur four to six weeks later, shortly after oviposition by adult worms, probably as an expression of hypersensitivity to ova and their products. Papulonodular lesions, similar to but not as devasting as those developing internally, may rarely appear months later at the perineum or distant cutaneous sites as a manifestation of granulomatous hypersensitivity to eggs and, very rarely, worms, accidentally carried there through collateral and anastomosing vascular pathways.     

From discovery to eradication of schistosomiasis in Japan: 1847-1996

Among the areas in Japan where schistosome infections have occurred for many years, three major areas were Katayama District, Kofu Basin and Chikugo River Basin and three minor areas were Numazu District, Tone River Basin and Obitsu River Bank. The presence of the disease had long been recognised in the Katayama Memoir written by Fujii (1847, in the Chinese Classics). The cause of this endemic disease had been studied by many researchers, and finally a new trematode, Schistosoma japonicum, was discovered by Katsurada in 1904 [Tokyo Iji Shinshi, Vol. 1371, pp. 13-32]. The route of percutaneous infection was proven by Fujinami & Nakamura (1909) [Kyoto Medical Journal, Vol. 6, pp. 224-252] using 17 calves. Miyairi & Suzuki (1913) [Tokyo Iji Shinshi, Vol. 1836, pp. 1961-1965] determined a small snail, Oncomelania nosophora, as being the intermediate host, and clarified the development of the schistosome in the snail. To kill schistosome eggs, human faecal matter ('night soil') was stored for 2 weeks or more before using as fertiliser. Control of the parasite used caustic lime and calcium cyanamide to kill eggs, cercariae and Oncomelania snails. Susceptible cows were replaced with horses, which were more resistant to infection as the animal of burden for agriculture. Ditches around the rice fields were cemented for destruction of snail habitats. For snail control, sodium pentachlorophenate (NaPCP) was sprayed extensively. Some wetlands were drained and reclaimed and in selected localities, the river bottom was dredged. Such projects were undertaken with government support and aided by community participation. Epidemiological surveys began in 1910, first at Kofu, and infected people were treated with sodium tartar emetic (Stibnal) after 1921. The total number of cases detected in Japan in 1920 was about 8000. This figure was reduced annually down to 438 by 1970. The last human case of new infection found in Japan was at Kofu in 1977. Although snails were eradicated in most areas by 1983, a limited number of uninfected snails remain at Kofu and Obitsu.     

The detection of Hammondia hammondi in Australia and the identification of a free-living intermediate host

A cat fed commercially prepared cat food and free-living rats (Rattus rattus and R. norvegicus) passed coccidian oocysts which were morphologically similar to Toxoplasma gondii. Mice dosed with these oocysts did not develop toxoplasmosis, but instead developed small, thin-walled parasitic cysts containing small bradyzoites in their striated muscles. These cysts measured 35 to 90 micron by 9 to 40 micron and they resembled cysts of Hammondia hammondi. Unlike T. gondii this coccidian parasite was shown to have an obligatory two-host cycle and consequently it is considered to be H. hammondi. This represents the first recorded detection of H. hammondi in Australia. The source of the H. hammondi infection was a Rattus rattus. This represents the first record of a natural intermediate host for H. hammondi.     

Production of IgE antibodies against the 22 kDa tegumental membrane-associated antigen of schistosomes is directed by the antigen itself

It has previously been reported that the predominant target of immunoglobulin E (IgE) recognition in sera from humans infected with Schistosoma japonicum in The Philippines or with S. mansoni in Kenya, is a 22 kDa tegumental membrane-associated schistosome antigen. In the present study, we demonstrate that the 22 kDa antigen can direct the production of antigen-specific IgE antibodies independently of schistosome infection and in the absence of any other parasite components or adjuvant. Three strains of mice were immunized using the purified, recombinant 22 kDa antigen of S. japonicum without the use of any adjuvant. Sera from all three strains of immunized mice, but not control animals, generated IgE antibodies specific for the native 22 kDa schistosome antigen in Western blots. Thus, the 22 kDa antigen itself must contain signals (presumably encoded by the primary amino acid sequence or by the secondary or tertiary structures of the molecule, or by a combination of these) which are sufficient to direct the isotype switch required for production of antigen-specific IgE.     

Intercellular adhesion molecule 1 is the major adhesion molecule expressed during schistosome granuloma formation

Endothelial cell adhesion molecules play a key role in inflammation by initiating leukocyte trafficking. One of the most complex inflammatory responses is the formation of a cellular granuloma. Expression of adhesion molecules during granuloma formation was investigated by using the murine host reaction to schistosome parasite eggs deposited in the liver as a model. By both immunohistochemistry and lymphocyte adhesion assays, the predominant interaction identified was between intercellular adhesion molecule 1 (ICAM-1) and its cognate integrin, leukocyte functional antigen 1 (LFA-1). ICAM-1 expression on sinusoidal endothelium was induced when eggs were first deposited in the liver, peaked in parallel with granuloma size, and was downregulated with modulation of the granuloma. Polyacrylamide beads coated with soluble parasite egg antigens could induce ICAM-1 expression on endothelial cells in vitro only in the presence of tumor necrosis factor alpha, a cytokine previously shown to be key to granuloma formation. A role for ICAM-1 in recruiting lymphocytes to the hepatic granuloma was also supported by the observation that lymphocytes preincubated with anti-LFA-1 antibody did not bind to granulomas in tissue sections. While ICAM-1 is the predominant adhesion molecule in schistosome egg granuloma formation in wild-type mice, when the ICAM-1 gene is knocked out, vascular cell adhesion molecule 1 is upregulated and granuloma formation is preserved.     

Fc epsilon receptor-positive cells are a major source of antigen-induced interleukin-4 in spleens of mice infected with Schistosoma mansoni

When cultured in vitro with either mitogen or parasite antigens, spleen cells from mice infected with Schistosoma mansoni produce significantly higher levels of IL-4 than splenocytes from control animals. Previous studies suggested that this increase in IL-4 production occurs because of a selective expansion of T helper type 2 (Th2) cells in infected mice. However, these experiments employed unfractionated spleen populations rather than purified T lymphocytes. Here we demonstrate that T-depleted spleen cells from infected animals synthesize high levels of interleukin-4 (IL-4), but no IL-5 when stimulated with parasite antigen in vitro. Nevertheless, when purified by sorting, T cells and non-B, non-T (NBNT) populations produced similar amounts of IL-4 in response to parasite antigen. The IL-4 producing NBNT cells were found to belong to an Fc epsilon receptor (Fc epsilon R)-positive population which after sort purification produced high levels of IL-4 (between 1000 and 2000 U of per 5 x 10(3) cells). FACS analysis revealed that these Fc epsilon R+ cells make up 0.53% of splenic NBNT cells in control animals while in 8-9-week-infected animals they increase to 3.8% of that population. In contrast, in mice with 8-week unisexual worm infections these cells comprise only 1.71% of NBNT cells, indicating that eggs are a major stimulus of the response. The expansion of Fc epsilon R+ cells and their production of IL-4 could be an important factor regulating the selection and induction of different CD4+ subsets in schistosome-infected hosts.     

Polymerase chain reaction-based risk assessment for Wilms tumor in sporadic aniridia

To investigate the prevalence of Lyme disease infection in Taiwan, we conducted a zoonotic survey for spirochetal infection in the small mammals. Ear tissues of trapped rodents collected from various localities in Taiwan were incubated into BSK-H culture medium and examined for the evidence of spirochetal infection by dark-field microscopy. Spirochetes cultured from six species of wild and peridomestic rodents and seven isolates, designated TWKM 1-7, were purified by serial dilution and membrane filtration. Infection was detected in 16.6% (53 of 320) of captured rodents and the highest infection rate (36.4%) was observed in the brown country rat (Rattus losea, Swinhoe). Higher infection rates based on the geographic distribution were observed in the eastern localities and on Kimmen Island. Reactivity with Borrelia burgdorferi-specific monoclonal antibodies and Western blot analysis indicated that these Taiwan isolates were closely related to the causative agent of Lyme disease, B. burgdorferi sensu lato. These results provide the first evidence of the existence of Lyme disease spirochetes in the Taiwan area.     

Monitoring of serologic immune parameters in inflammatory skin diseases

This paper deals with the correlation of clinical scoring and serologic markers of inflammation in atopic dermatitis and psoriasis. Serum eosinophil cationic protein (ECP), soluble interleukin-2 receptor (sIL-2R), total serum IgE, IgG and IgM anti-IgE antibodies, and IgE immune complexes were evaluated in monitoring inflammatory skin diseases such as atopic dermatitis and psoriasis. Well-established clinical activity scores were used as standards in recording skin improvement under treatment in a clinical setting. Serum ECP was found to be increased in both atopic dermatitis and psoriasis patients compared to normal controls; sIL-2R and IgE immune complexes were increased only in atopics with increased serum IgE. Anti-IgE antibodies did not show any deviation in both groups of patients. There was a significant elevation of sIL-2R and IgE immune complexes and a nonsignificant elevation of ECP in high-IgE atopics in comparison to those with normal serum IgE. In both groups of patients, there was a significant reduction of ECP and sIL-2R accompanying the improving skin condition. Serum IgE and the other immune parameters failed to respond. In contrast to other studies, serum ECP failed to correspond significantly with disease activity in our study. Our results showed measurable changes of ECP and sIL-2R for atopic dermatitis and/or psoriasis under treatment, but comparison to clinical scores remains difficult due to the different basis of the two systems. The only significant correlation was established for relative changes in sIL-2R and psoriasis area and intensity (PASI), a correlation which might be a useful approach in psoriasis.     

Auditory Categorization of Complex Sounds by Rats (Rattus norvegicus).

Little research has explored the auditory categorization abilities of mammals. To better understand these processes, the authors tested the abilities of rats (Rattus norvegicus) to categorize multidimensional acoustic stimuli by using a classic category-learning task developed by R. N. Shepard, C. I. Hovland, and H. M. Jenkins (1961). Rats proved to be able to categorize 8 complex sounds on the basis of either the direction or rate of frequency modulation but not on the basis of the range of frequency modulation. Rats' categorization abilities were limited but improved slowly and incrementally, suggesting that learning was not facilitated by selective attention to acoustic dimensions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A small-scale survey of hantavirus in mammals from Indiana

In order to determine if hantaviruses were present in mice and other small mammals in Indiana (USA), small mammals were trapped in Brown, LaPorte, Tippecanoe and Whitley counties. Sixty-seven small mammals were trapped during August and September 1994. Sixty-three Peromyscus leucopus, one Microtus pennsylvanicus, one Zapus hudsonius and two Blarina brevicauda were captured and tested for hantaviruses. Six P. leucopus were found to have antibody to Sin Nombre virus (SN) by IgG ELISA, and a 139 bp fragment of SN-like hantavirus was amplified from five of them. All six of the positive P. leucopus were from LaPorte County. No other small mammals had evidence of infection with SN virus. This study presents the first report of Sin Nombre-like hantavirus in P. leucopus from Indiana.     

What can monotremes tell us about brain evolution?

The present review outlines studies of electrophsyiological organization, cortical architecture and thalmocortical and corticocortical connections in monotremes. Results of these studies indicate that the neocortex of monotremes has many features in common with other mammals. In particular, monotremes have at least two, and in some instances three, sensory fields for each modality, as well as regions of bimodal cortex. The internal organization of cortical fields and thalamocortical projection patterns are also similar to those described for other mammals. However, unlike most mammals investigated, the monotreme neocortex has cortical connections between primary sensory fields, such as SI and VI. The results of this analysis lead us to pose the question of what monotremes can tell us about brain evolution. Monotremes alone can tell us very little about the evolutionary process, or the construction of complex neural networks, as an individual species represents only a single example of what the process is capable of generating. Perhaps a better question is: what can comparative studies tell us about brain evolution? Monotreme brains, when compared with the brains of other animals, can provide some answers to questions about the evolution of the neocortex, the historical precedence of some features over others, and how basic circuits were modified in different lineages. This, in turn, allows us to appreciate how normal circuits function, and to pose very specific questions regarding the development of the neocortex.     

DNA-based vaccination using Schistosoma japonicum (Asian blood-fluke) genes

We have examined the efficacy of nucleic acid vaccination in inducing immunity to the multicellular parasite, Schistosoma japonicum, a trematode worm responsible for causing schistosomiasis in humans and other mammalian species. A panel of Schistosoma japonicum cDNAs were cloned into eukaryotic expression vectors, injected into animals, and tested for immunogenicity. The cDNAs tested encoded 26- and 28-kDa glutathione-S-transferases, calreticulin, glyceraldehyde-3-phosphate dehydrogenase, a 22.6 kDa membrane-associated antigen, a 14 kDa fatty-acid binding protein, fragments of paramyosin, full-length paramyosin, and a novel gene comprising the 26 kDa glutathione-S-transferase fused to a fragment of paramyosin cDNA. The paramyosin gene constructs, including the fusion, were all able to induce anti-paramyosin antibodies; with the fragments of paramyosin these were of the IgG1, IgG2a and IgG2b isotypes. In contrast, none of the other schistosome cDNAs tested were able to induce detectable antibody responses. The anti-paramyosin antibodies did not protect mice challenged with cercariae of S. japonicum.     

Urethral advancement and glanuloplasty (UGPI): a modification of the MAGPI procedure for distal hypospadias

Hyperkeratotic dermatitis of athymic nude mice is an infectious disease caused by a coryneform bacterium. During the spring of 1995, outbreaks of hyperkeratotic dermatitis were observed in several nude mice facilities in northern Italy. In this report we describe the clinical, histopathological and microbiological features of the disease in two different animal facilities. Affected animals showed a typical 'scaly' appearance with small white flakes of material adherent to the skin. In one of the outbreaks (facility 2) the lesions were less severe and involved only limited areas of the body. The infection spread very quickly and the morbidity reached more than 80% in a few days, while the mortality was about 1%. The lesions resolved spontaneously within 7-10 days. Histological examination of affected skin revealed orthokeratotic hyperkeratosis, acanthosis and dermal inflammatory infiltration which were more severe in mice from facility 1. In Gram-stained sections groups of rods consistent with coryneform bacteria were detectable in the keratin layers covering the epidermal surface. A coryneform bacterium, biochemically typed as Corynebacterium bovis, was isolated from 11 out of 11 mice from facility 1 and from 8 out of 11 mice from facility 2.