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Biomedical subjects

A Spielman

Publications and source records attributed to A Spielman.

At least 199 records · Page 11Linked to original sources
PubMed1982

Penetration of the peritrophic membrane of the tick by Babesia microti.

A peritrophic membrane (PM) has been demonstrated in the gut of feeding larvae, nymphs, and adults of the tick Ixodes dammini. This is the first report of a PM in ticks. This temporary structure divides the lumen of the gut into two compartments, an endoperitrophic space, the lumen proper, and an ectoperitrophic space located between the PM and the epithelial cells of the gut wall. The PM is a mechanical barrier and even such small particles as ribosomes derived from ingested reticulocytes are retained in the lumen proper; they are never found in the ectoperitrophic compartment. In Ixodes dammini fed on hamsters infected with Babesia microti some of the parasites are found in the ectoperitrophic space. This passage is accomplished by a highly specialized organelle, the arrowhead, which develops in some Babesia during their metamorphosis in the gut of the vector. The arrowhead, while passing through the PM, changes its fine structure and loses its internal organization as if releasing some of its contents. Its disintegration continues and it disappears shortly after the Babesia have entered the epithelial cells. Only Babesia equipped with the arrowhead structure are able to cross the PM. This is the first documented case of a parasite traversing a solidified PM.

Animals↗
PubMed1982

Brugia malayi microfilariae from the peritoneal cavity of jirds vary in their ability to penetrate the mosquito midgut.

Development in mosquitoes of Brugia malayi microfilariae obtained from the blood of jirds was compared to that of microfilariae from the peritoneal cavity. Penetration of the mosquito midgut wall as well as development into third-stage larvae was assessed. About 70% of blood-borne microfilariae penetrated the midgut wall whether ingested directly from a microfilaremic jird or from a membrane feeder containing blood from the same donor. In contrast, less than 30% of microfilariae from the peritoneal cavity penetrated the midgut wall. Microfilariae in the peritoneal cavity of jirds vary in ability to penetrate the midgut of mosquitoes; some penetrate as rapidly as do blood-borne microfilariae, others penetrate more slowly, and most fail to penetrate the midgut. Regardless of origin, microfilariae that penetrated the midgut wall developed into third-stage larvae.

Aedes↗
PubMed1981

Xerostomia--diagnosis and treatment.

Seventy-one patients complaining of mouth dryness were examined. Decreased salivary rate of flow was found in fifty-six. Twenty-two patients did not respond to stimulation and were treated with artificial saliva. The thirty-four responding patients were treated with a mouthwash containing citric acid (Saliram). Of the patients using Saliram, 91 percent were satisfied with the results, and in 16 percent of these an increase in salivation was observed and persisted after treatment was discontinued.

Aged↗
PubMed1981

Sialochemistry for diagnosis of Sjögren's syndrome in xerostomic patients.

The flow rate and composition of whole unstimulated saliva were measured in fifteen healthy controls and in forty-eight xerostomic patients, fourteen suffering from xerostomia per se, twenty-two from xerostomia with keratoconjunctivitis sicca (KCS), and twelve from xerostomia, KCS, and rheumatoid arthritis. A significant lower salivary flow rate was found in all the xerostomic patients. Sodium, potassium, and IgA concentrations were significantly elevated in the KCS and in the RA + KCS group in comparison with the patients who had xerostomia per se and with the healthy controls. Sialochemistry is thus recommended for the diagnosis of Sjögren's syndrome in xerostomic patients.

Female↗
PubMed1981

Tick transmission of Babesia microti to rhesus monkeys (Macaca mulatta).

To determine whether Ixodes dammini is capable of transmitting Babesia microti to primates, infected nymphal ticks were allowed to feed on five Macaca mulatta. The monkeys were then followed for at least 60 days with daily thick blood smears for evidence of infection. Patent B. microti parasitemia developed in four of the five animals. Prepatent periods were 13, 18, 20, and 28 days. Maximum parasitemia ranged from 83 to 7,068 organisms/mm3 blood. Splenectomy 15-17 months after exposure to ticks results in recurrences of parasitemia in three of the four infected monkeys.

Animals↗
PubMed1981

Reservoir hosts of human babesiosis on Nantucket Island.

The host range of Babesia microti was studied on Nantucket Island in order to identify the enzootic reservoir of this human pathogen. White-footed mice (Peromyscus leucopus) were more frequently parasitized than were other indigenous animals. Infection was ubiquitous in locations where deer were abundant. Mice were most frequently parasitemic during spring and summer and adults more frequently than juveniles. Parasitemia, which was rarely intense, was sustained for as long as 4 months. Mice lived as long as 10 months, and juveniles were most abundant during early summer. Prevalence of zoonotic infection, in certain locations, appeared to be inversely correlated with abundance of mice. B. microti was present solely in regions harboring deer.

Animal Population Groups↗
PubMed1981

Epidemiology of human babesiosis on Nantucket Island.

Between 1969 and 1977, 14 persons with parasitologically confirmed Babesia microti infections and seven persons with antibody titers to B. microti greater than or equal to 1:1,024 were identified on Nantucket Island, Massachusetts. Nineteen of these 21 persons were interviewed. About half were permanent residents of Nantucket; the others spent most of their summers on the island. There were 12 women and seven men. Patients ranged in age from 23 to 86 years; all of those with parasitologically confirmed infections were at least 49 years old. Fifteen patients had illnesses characterized by fever, chills, myalgia and fatigue. Five reported being bitten by a tick from 7 to 28 days before the onset of illness. Most cases occurred during July or August. There appeared to be no association between B. microti infection and direct contact with wild or domestic animals or specific outdoor activities. The unusual age distribution of patients with parasitologically confirmed B. microti infections may result because older persons tend to have more severe illnesses and thus are more likely to come to medical attention.

Adolescent↗
PubMed1980

Human babesiosis on Nantucket Island: prevalence of Babesia microti in ticks.

In order to derive direct evidence implicating Ixodes dammini as a vector of human babesiosis, we determined the prevalence of Babesia microti infection in nymphal I. dammini collected on Nantucket Island. In experiments in the laboratory we found that nymphs remained attached to hamsters for about 3 days. Babesial infection was transmitted more often during 54 hours of attachment then during 36 or 48 hours. Since parasites were demonstrable in salivary glands solely after 48 hours, we derived an engorgement index for identifying ticks attached for 2 days or more. Of 156 nymphal I. dammini, collected from white-footed mice in 1979, 86 were engorged sufficiently to satisfy this index of attachment, and the salivary glands of four contained B. microti parasites. This demonstrates that about 5% of nymphal I. dammini are infected in nature. Risk of human infection can be reduced by prompt removal of attached ticks.

Animals↗
PubMed1980

Methods for detecting Babesia microti infection in wild rodents.

We compared various methods for detecting Babesia microti infection in white-footed mice (Peromyscus leucopus) captured in enzootic regions of Massachusetts. The most sensitive method tested involved inoculating blood from wild rodents into hamsters. One month postinoculation proved to be the optimal time for microscopically examining blood of inoculated hamsters. With this method, as few as 300 organisms produced patent infection. Prior splenectomy of hamsters did not increase susceptibility to infection. For direct study of captured animals, a Giemsa-stained, thin blood-film prepared from the animal's tail was the most convenient method tested. However, this method detected only 61% of infections identified by hamster inoculation.

Animals↗
PubMed1979

Canine Babesia new to North America.

A domestic dog residing in New England suffered a fatal febrile illness caused by a Babesia infection. The morphology of these intraerythrocytic protozoa and the range of hosts that could be infected experimentally suggested that the parasite was B. gibsoni. Although this tick-bourne disease is enzootic in wild and domestic Canidae in Africa and Asia, it appears to be new to the Americas.

Animals↗
PubMed1979

Differential distribution of peridomestic Aedes mosquitoes on Grand Bahama Island.

Aedes aegypti, on Grand Bahama Island, is restricted to certain western towns, whereas A. bahamensis is more generally distributed. During 14 years of observation, the range of A. Aegypti has extended 8 km and now includes the major tourist centre. Relocation of discarded automobile tires is an important mechanism for such spread. We suggest that the presence of A. bahamensis restrains colonization by A. aegypti, and thereby helps to protect human populations from A. aegypti-borne disease.

Aedes↗