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Biomedical subjects

J H Theis

Publications and source records attributed to J H Theis.

At least 19 recordsLinked to original sources
PubMed2006

Biological, seasonal and environmental factors associated with Pulex irritans infestation of dairy goats in Greece.

The objectives of the present study were to study the fauna of fleas infesting dairy goats in Greece, the spectrum of hosts each flea species infests, identify risk factors in the environment, and goat management practices that favour flea infestation of goats, and describe the seasonal variation of infestation in goats. For this purpose, a total of 64 herds, with a history of flea infestation in goats, were visited during June and July of 2002 for data collection on flea burdens, species of fleas on goats, and other farm or pet animal species in the farm. Also data were collected on herd characteristics and management along with the flea infestation status of the village where it was located through a questionnaire survey. Data on elevation and climatic characteristics of the villages where the herds were located were also used in the study. All fleas collected from goats, sheep, pigs, and cattle were identified as being Pulex irritans. All fleas collected from cats were identified as being Ctenocephalides felis. Dogs were infested either with P. irritans, C. canis, or C. felis, or with both C. canis and C. felis. Kids had a significantly higher flea burden than goats and the Skopelos breed had the highest flea burden of all breeds followed in diminishing order by the breeds Capra prisca, Saanen cross mix, and Alpine cross mix (p < 0.05). The gender of the animal had no significant effect on flea burden. Factors significantly affecting the flea burden of goats were duration of flea infestation in the herd, type of flea control, and manure imported prior to the appearance of fleas in the herd (p < 0.05). The flea burden of goats was highest during summer and lowest during winter (p < 0.01), with complete an absence of infestation in January and February. Finally, a significant difference (p < 0.05) was found between the average annual temperature of villages with flea infestation (15.59 degrees C) and villages without flea infestation (17.14 degrees C). It was concluded that P. irritans was a true infestation of goats in Greece.

Age Factors↗
PubMed2005

Public health aspects of dirofilariasis in the United States.

Coin lesions in the human lung present significant differential diagnostic problems to the physician. There are at least 20 known causes of such lesions, including neoplastic lesions, infectious diseases, and granulomas. The human medical literature contains many misconceptions about the life cycle of Dirofilaria immitis, including the method of entry of the infective-stage larvae and the development of the young adult worm. These misconceptions have obscured the recognition of the clinical presentation of pulmonary dirofilariasis and the potential for D. immitis to lodge in many other areas of the human body besides the lung. Exposure to infective larvae of D. immitis is more common in humans than is currently recognized. Reported cases in humans reflect the prevalence in the canine population in areas of the United States. The veterinary literature provides compelling evidence that D. immitis is a vascular parasite, not an intracardiac one. Its presence in the right ventricle is a post-mortem artifact, because it has never been shown to be there by echocardiography or angiography in a living dog, even though these techniques have demonstrated adult D. immitis in the pulmonary, femoral, and hepatic arteries; posterior vena cava; and right atrium of live dogs. Physicians have taken the name "heartworm" literally, believing that the worm lives in the heart and only after it dies does it embolize to the pulmonary artery. However, the coin lesion is spherical in shape, not pyramidal, as embolic infarcts to the lung in humans are known to be. The coin lesion is an end-stage result of the parasite's death in the vascular bed of the lungs and the stimulation of a pneumonitis followed by granuloma formation. This pneumonitis phase of human pulmonary dirofilariasis is often not recognized by the radiologist because of the way pneumonitis is diagnosed and treated and because the developing nodule is obscured by the lung inflammation. Serologic methods for use in humans are needed for clinical evaluations of patients with pneumonitis living in highly enzootic D. immitis regions. As well, epidemiological surveys are needed to determine the real extent of this zoonotic infection.

Animals↗
PubMed2005

Neurocysticercosis: a review.

BACKGROUND: In North America, the largest number of neurosurgical cases stemming from parasitic infections involves the larval form of Taenia solium, the infectious organism causing neurocysticercosis. This infection of the central nervous system (CNS) is most commonly seen in areas with significant immigrant populations and can often present particular challenges to treating physicians. METHODS: A review of the literature was performed, highlighting the epidemiology, parasitology, and clinical manifestations of neurocysticercosis. Particular attention was paid to 4 locations of neurocysticercosis lesions: parenchymal, subarachnoid/cisternal, intraventricular, and spinal. RESULTS: Both medical and surgical interventions may be necessary for adequate treatment of neurocysticercosis, depending on various factors, including location of lesion. CONCLUSIONS: A review of neurocysticercosis, with particular attention paid to location of disease involvement in the CNS, provides important information to the clinical management of this disease.

Humans↗
PubMed2005

Parasitic central nervous system infections: echinococcus and schistosoma.

Central nervous system (CNS) manifestations of Echinococcus and Schistosoma infections occur throughout the world, with incidence increasing in developed regions. A detailed literature review generated a current summary on epidemiology, parasitology, pathology, clinical manifestations, imaging studies, diagnosis, and treatment of neuroechinococcosis and neuroschistosomiasis. Recent advancements have been made in diagnosis, treatment, and prevention of these parasitic CNS infections. Ongoing advancements in neuroimaging and diagnostic studies, as well as efforts to better understand the parasite genome and host-parasite relationships, will likely continue to improve patient management.

Animals↗
PubMed2000

Vector competence of two species of mosquitoes (Diptera: Culicidae) from southern California for Dirofilaria immitis (Filariidea: Onchocercidae).

Two species of mosquitoes reared to adults from field-collected larvae or egg rafts in or near Los Angeles County, CA, were exposed to dogs with known levels of Dirofilaria immitis (Leidy) microfilariae per 20 cubic millimeters of blood. Aedes taeniorhynchus (Wiedemann) readily blood fed on an infected dog ingested microfilariae but did not become infected. Culiseta incidens (Thomson) also fed on an infected dog became infected, and 10% of the microfilariae developed to the L3 stage. Cs. incidens is a peridomestic species broadly distributed in Los Angeles County and abundant from February through December. The wide distribution of this species as well as its long annual period of reproductive activity in Los Angeles County may contribute to its potential as a vector of D. immitis.

Aedes↗
PubMed2000

Cutaneous schistosomiasis: report of a case and review of the literature.

Cutaneous disease is a previously reported but unusual presentation for schistosomiasis. We report a case of Schistosoma haematobium infection that appeared 3 years after exposure, with skin lesions as the sole manifestation. The diagnosis was made on the basis of a routine skin biopsy and the patient did well after therapy with praziquantel. Dermatologists should be aware of this presentation of schistosomiasis when evaluating patients with unusual skin lesions who have traveled in areas where schistosomiasis is endemic.

Adult↗
PubMed1996

DNA-confirmed Taenia solium cysticercosis in black bears (Ursus americanus) from California.

Three cases of cysticercosis in black bears (Ursus americanus) in three northern California counties between 1990 and 1994 have been identified as due to the tapeworm Taenia solium. Both morphologic characteristics as well as the presence of T. solium mitochondria cytochrome oxidase I gene sequences, as detected by the polymerase chain reaction, confirmed the diagnosis. The number and geographic separation of the cases suggests that infection of the bears was not due to a single contamination. Humans infected with the definitive stage of T. solium are the probable source of cysticercosis for bears, as well as other humans. This is the first confirmation of cysticercosis due to T. solium in a black bear in North America.

Animals↗
PubMed1994

Detection by immunoblot assay of antibodies to Taenia solium cysticerci in sera from residents of rural communities and from epileptic patients in Bali, Indonesia.

Several studies from Bali have indicated the presence of Taenia solium. Relatively little has been reported, however, implicating human exposure to this parasite on Bali based upon the prevalence of anti-T. solium antibodies in asymptomatic and epileptic individuals. This study was conducted to determine by immunoblot assay and ELISA the frequency of anti-cysticercus antibodies in two groups of Balinese. Among 746 residents of four ecologic zones, 94 (13%) were positive by immunoblot. Of 74 epileptic patients from throughout the island, 10 (14%) were positive by immunoblot and 8 (11%) by ELISA; however, only 4 (22%) of the 18 sera positive in either test were positive in both assays. The previously defined high specificity and sensitivity of immunoblot indicates that T. solium cysticercosis is well established in Bali and that a significant amount of epilepsy may be due to neurocysticercosis.

Adolescent↗
PubMed1992

Humoral responses following immunization with Leishmania infantum (ex. Oklahoma): a comparison of adjuvant efficacy in the antibody responses of Balb-C mice.

Adjuvants are commonly used in immunization protocols for the purpose of augmenting immune responses to antigens. The antigenic profile of Leishmania infantum (ex. Oklahoma) is described and the efficacies of three adjuvants delivered coincidentally with killed promastigotes are compared, by measuring relative serologic responses of Balb-C mice to specific antigenic determinants. Western blotting techniques were employed to visualize humoral responses to isolated antigens; serologic profiles were compared and contrasted. Four immunization protocols utilizing Freund's complete adjuvant, glucan adjuvant, lipovant adjuvant or phosphate-buffered saline, in conjunction with killed L. infantum (ex. Oklahoma) promastigotes were executed in parallel. All groups receiving adjuvant protocols developed enhanced serologic responsiveness. Similar profiles were observed in mice treated with glucan or lipovant. Animals receiving promastigotes in Freund's complete adjuvant also developed strong humoral responses, binding cross-reactive epitopes not recognized by other groups. Our findings indicate that glucan and lipovant present effective adjuvant alternatives, to Freund's complete adjuvant and may be of value in immunization against visceral leishmaniasis.

Adjuvants, Immunologic↗
PubMed1992

Seasonal prevalence of Taenia taeniaeformis: relationship to age, sex, reproduction and abundance of an intermediate host (Peromyscus maniculatus).

Livers from 4,501 deer mice (Peromyscus maniculatus) collected from a weedy habitat in northeastern California during 48 consecutive monthly samplings were examined microscopically for Taenia taeniaeformis larva. Although there were pronounced seasonal fluctuations in host density, there were no significant annual or season-related differences in cestode intensities in adult deer mice. There were no significant differences in prevalences associated with sex of the host, nor were there significant changes in level of reproduction noted between infected and non-infected hosts. There were, however, significant differences in prevalences between young (1.2%) and adult (4.2%) hosts. Plausible mechanisms for this age-related difference in prevalence rates include (1) differential susceptibility due to the activity pattern of adult mice and/or (2) passive immunity in neonates as a result of colostrum- and/or transplacentally-transferred immunoglobulins and (3) capture of subadult animals before they had completed the period of highest susceptibility to T. taeniaeformis. Density of larvae per mouse liver was determined during a 21 mo consecutive period. The intensity of T. taeniaeformis larvae was not significantly different between the sexes of the adult mice. The larval stage showed an overdispersion pattern within the adult population. These results suggest that determinations of T. taeniaeformis abundances can be accurately made, at least in this P. maniculatus population, at any time of the year provided adjustment is made for the relative age structure of the host population.

Age Factors↗
PubMed1990

Change in the isoenzyme composition of acid phosphatase in murine peritoneal macrophages exposed to or infected with Trypanosoma cruzi.

The effect of infection with Trypanosoma cruzi on the activity and isoenzyme composition of acid phosphatase within individual murine peritoneal macrophages maintained in vitro was studied. Concentrations of acid phosphatase activity and number of intracellular parasites were quantitated by using a computer-assisted cytospectrophotometry system. Changes in the isoenzyme composition of macrophages during infection with T. cruzi were detected by comparing the patterns of acid phosphatase levels between macrophages treated in the absence and presence of an enzyme inhibitor. It was observed that the concentration levels of acid phosphatase activity in macrophages did not change significantly by infection with T. cruzi. Also, the concentration levels of acid phosphatase activity did not change in macrophages uninfected but exposed to T. cruzi. On the other hand, the isoenzyme composition of acid phosphatase did change in macrophages exposed to or infected with T. cruzi. These results demonstrate that Trypanosoma cruzi affects the acid phosphatase composition of macrophages.

Acid Phosphatase↗
PubMed1989

Decrease of acid phosphatase activity in murine peritoneal macrophages infected with Leishmania donovani.

The effect of infection with Leishmania donovani on the activity and isoenzyme composition of acid phosphatase within individual murine peritoneal macrophages maintained in vitro was studied. Concentrations of acid phosphatase activity and number of intracellular parasites were quantitated using a computer-assisted cytospectrophotometry system. Changes in the isoenzyme composition of macrophages during infection with L. donovani were detected by comparing the patterns of acid phosphatase levels between macrophages treated in the absence and presence of an enzyme inhibitor. It was observed that the concentration levels of acid phosphatase activity in macrophages were decreased significantly by infection with L. donovani. An inverse relation existed between concentration of acid phosphatase activity and the number of intracellular L. donovani. Reduced concentrations of acid phosphatase activity were also observed in macrophages uninfected but exposed to L. donovani. The isoenzyme composition in macrophages did not change during the course of infection with L. donovani. These results demonstrate that L. donovani reduces the acid phosphatase activity of macrophages.

Acid Phosphatase↗