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Biomedical subjects

P Prociv

Publications and source records attributed to P Prociv.

At least 37 records · Page 2Linked to original sources
PubMed1998

Cerebrospinal angiostrongyliasis in five captive tamarins (Sanguinus spp).

Four cotton-top tamarins (Sanguinus oedipus oedipus) and one emperor tamarin (S imperator subgrisescens) housed in a zoo became depressed, anorexic, paraparetic and eventually paralysed. The animals died within 5 days to 18 months of the appearance of clinical signs. Histological examination showed nonsuppurative and eosinophilic meningoencephalitis, and metastrongyle nematode larvae were found within subarachnoid spaces of all animals and within the spinal cord of one. Intact larvae with features consistent with Angiostrongylus cantonensis were recovered from the brain of one animal. This parasite is the classical cause of eosinophilic meningoencephalitis in many parts of the world and the diagnosis can be strongly suspected on clinical grounds. In endemic areas like south-east Queensland, protection of captive animals against infection with A cantonensis is a difficult balance between providing a stimulating, natural setting and eliminating potentially infectious definitive, intermediate and paratenic hosts. This is the first report of cerebrospinal angiostrongyliasis in tamarins and nonhuman primates in Australia.

Angiostrongylus cantonensis↗
PubMed1996

Acasp, a gene encoding a cathepsin D-like aspartic protease from the hookworm Ancylostoma caninum.

Intestinal infection with the zoonotic hookworm Ancylostoma caninum can provoke human eosinophilic enteritis. A cDNA was isolated from A. caninum, using an oligonucleotide primer designed to hybridize to the region encoding the consensus, catalytic site residues D32TGSSNLW of aspartic proteases. This novel cDNA encoded an aspartic protease zymogen of 422 amino acids, exhibiting 47% identity to the lysosomal aspartic protease of Aedes aegypti, 46% identity to the aspartic protease of Schistosoma japonicum, and 48.5% to human cathepsin D. Its deduced structure differed from that of cathepsin D in the loop 2 "flap," which holds the substrate at the active site, and by the presence of a COOH-terminal extension of approximately 30 residues.

Amino Acid Sequence↗
PubMed1996

Human enteric infection with Ancylostoma caninum: hookworms reappraised in the light of a "new" zoonosis.

Recent studies in northeastern Australia indicate that enteric infection with Ancylostoma caninum is a leading cause of human eosinophilic enteritis. Much more frequent accompaniments of this infection are obscure abdominal pain with or without blood eosinophilia, while a large part of the population is probably infected asymptomatically. These conclusions are based on extensive serological investigations in patients and control subjects, as well as 15 cases in which single, adult hookworms were identified in situ in patients. In no case has more than one worm been identified, and none has been fully mature, so the infections have never been patent. Aphthous ulcers of the terminal ileum, caecum and colon have been seen in association with this infection and have also been observed in almost 5% of patients who are colonoscoped in north Queensland. Serodiagnosis has relied on an IgG and IgE ELISA using excretory-secretory antigens from adult A. caninum, but Western blot using these antigens to identify IgG4 antibodies to a protein of molecular weight 68 kDa (Ac68) promises to be more specific and sensitive. However, identical antigens appear to be secreted by the anthropophilic hookworms as well. The clinical, public health and biological significance of these findings are discussed in detail.

Adult↗
PubMed1996

Immunoglobulin G subclass antibodies against excretory/secretory antigens of Ancylostoma caninum in human enteric infections.

Most patients with proven or suspected enteric infection with the common hookworm of dogs, Ancylostoma caninum, produce immunoglobulin G (IgG) and IgE antibodies to an immunodominant excretory/secretory antigen (Ac68) of the parasite. These antibodies were detected in both enzyme-linked immunosorbent assay (ELISA) and Western blots; the Western blot to detect IgG antibodies to Ac68 was the most specific and sensitive. The subclasses of IgG of the antibody response to the parasite were analyzed using Western blots with anti-IgG subclass-specific monoclonal antibodies as marker systems in an attempt to further improve the specificity of the assay. Eight patients with confirmed enteric infections with A. caninum (positive controls) were tested; six had antibodies in all IgG subclasses against Ac68. Twenty sera from patients with suspected enteric infection with A. caninum (manifested as eosinophilic enteritis or unexplained abdominal pain with peripheral eosinophilia) were tested; 16 had total IgG antibodies to Ac68, while IgG1, IgG2, IgG3, and IgG4 responses were found in 11, 10, 9, and 12 of these sera, respectively. Small numbers of sera from groups of patients infected with other helminths and from healthy blood donors had various combinations of IgG, IgG1, IgG2, and IgG3 antibodies to Ac68, but none of these sera had IgG4 antibodies to Ac68. Sera from all nine patients with human hookworm infection had IgG, IgG1, IgG2, and IgG3 antibodies to Ac68 and eight of the nine were also positive for IgG4 antibodies. These results indicate the Western blot to detect IgG4 antibodies to Ac68 is the most reliable immunodiagnostic test yet described for enteric infection with A. caninum, although this test does not discriminate between infections with human and canine hookworms.

Ancylostoma↗
PubMed1995

Deaths of Australian travellers overseas.

OBJECTIVE: To determine the number and causes of deaths of Australian citizens who died overseas in a 12-month period. DESIGN: Retrospective survey of deaths reported to the Australian Department of Foreign Affairs and Trade by Australian embassies, high commissions and consulates for the period July 1992 to June 1993. Data on Australians travelling overseas were obtained from the Australian Bureau of Statistics. RESULTS: During the year 1992-1993, 2,299,500 Australians travelled overseas for less than 12 months (short term travellers), with an estimated mean trip duration of 6.3 weeks. Another 65,450 left for more than 12 months (long term travellers), and 27,910 left permanently (residents). Of the 421 recorded deaths, 289 were in short term travellers, 108 in long term travellers/residents and 24 in members of work parties. The annual crude mortality rate for short term travellers and work party members was estimated at about 0.1%. Men outnumbered women almost 4:1. Death rates increased with age, reflecting underlying medical problems in older travellers, with heart disease being the leading cause (146 deaths, 35%). Fatal trauma predominated in younger people. Accidents, mainly in traffic, accounted for 77 deaths (18%) and infections for 10 (2.4%), including two cases of malaria. Death rates varied between geographical regions, with New Zealand being the safest destination. CONCLUSIONS: The risk of an Australian dying while travelling overseas is probably little different from that while staying home. The low level of fatal infections may result from preventive measures. Travellers should be aware of the danger of accidents, particularly traffic accidents, while overseas.

Adolescent↗
PubMed1995

The changing epidemiology of human hookworm infection in Australia.

OBJECTIVE: To document the distribution of human hookworm infection in Australia. DESIGN: A retrospective study of published data and accessible archival records. METHODS: The core data were derived from the report of the Australian Hookworm Campaign, annual reports of various State health departments and the Queensland Institute of Medical Research, and unpublished files of the former Queensland Aboriginal Health Programme. FINDINGS: Today, hookworm infection is endemic only among Aboriginal communities of northern Western Australia and the Northern Territory, where Ancylostoma duodenale may be the sole species. Early this century, infection was also established in Queensland and northern New South Wales, in both Aboriginal and white communities, and Necator americanus predominated. The origin of these parasites is obscure. Sustained control programs seem to have eradicated hookworms from Queensland. CONCLUSIONS: Improved sanitation, hygiene and chemotherapy have eliminated hookworms from white populations of Australia. Continued anthelminthic campaigns will also clear the parasites from Aboriginal communities, but unless living conditions improve significantly infection will recur.

Ancylostomiasis↗
PubMed1995

Characterization and localization of cathepsin B proteinases expressed by adult Ancylostoma caninum hookworms.

The hookworm Ancylostoma caninum induces human eosinophilic enteritis (EE), probably via allergic responses to its secretions. Cysteine and metallo-proteinases may be the components of these secretions that elicit hypersensitivity reactions. In order to characterize genes encoding cysteine proteinases (CP) secreted by A. caninum, an adult hookworm cDNA library was constructed and screened with a cloned fragment of a hookworm CP gene. This fragment was obtained using consensus oligonucleotide, CP-gene-specific primers in the polymerase chain reaction. cDNAs encoding two CPs were obtained from the library and sequenced. The first gene, AcCP-1, encoded a cathepsin B-like zymogen CP of 343 amino acids (aa), predicted to be processed in vivo into a mature CP of 255 aa. Closest nucleotide identities were to Haemonchus contortus cysteine protease (61%) and to human cathepsin B (60%). The second gene, AcCP-2, encoded a mature CP of 254 aa, that showed 86% identity to AcCP-1, and 58% and 47% identity to bovine cathepsin B and human cathepsin B, respectively. Rabbit antisera raised against recombinant AcCP-1 reacted with esophageal, amphidial and excretory glands in formalin-fixed, paraffin embedded sections of both male and female adult hookworms, and with an antigen of approx. 40 kDa in Western blot analysis of excretory/secretory products from adult hookworms. Together, these immuno-hybridization results strongly suggest that the CP encoded by the AcCP-1 gene is secreted by hookworms. These are the first reported CP genes from hookworms. Proteinases encoded by these genes may be responsible for the CP activity that we have shown previously to be secreted by adult A. caninum.

Amino Acid Sequence↗
PubMed1995

Eosinophilic enteritis in northeastern Australia. Pathology, association with Ancylostoma caninum, and implications.

While eosinophilic gastroenteritis is considered a rare condition, eosinophilic enteritis without gastric involvement is quite common in northeastern Australia. We present 79 patients with biopsy-proven eosinophilic enteritis, 70 seen since 1987. In 10 patients, eosinophilic enteritis was associated with infection by single, sexually immature, adult hookworms, most positively identified as the common dog hookworm Ancylostoma caninum. An additional 22 patients (of 34 tested) had serological evidence of A. caninum exposure. The essential pathology, i.e., edema and eosinophilic infiltration of the gut wall, ascites, and regional lymphadenopathy, was identical to that seen in eosinophilic gastroenteritis. Additional, more specific features included pathological reactions centered on attached worms, mucosal alterations and ulcers considered to be hookworm bite sites, and submucosal and lymph node granulomas with central eosinophil degranulation and degradation products. Since A. caninum has an almost worldwide distribution, it is probable that A. caninum-induced eosinophilic enteritis occurs outside Australia. We show that the worm is easily overlooked in pathological specimens and that care is required to preserve worms intact for specific parasitological identification. The clinical and pathological features were similar to those seen in another human enteric helminthic zoonosis, anisakiasis. The possibility that there are yet other undiscovered intestinal zoonoses remains.

Adolescent↗
PubMed1995

Immunohistochemical localization of excretory/secretory antigens in adult Ancylostoma caninum using monoclonal antibodies and infected human sera.

Human eosinophilic enteritis (EE) may result from hypersensitivity to the excretory/secretory (ES) antigens of adult Ancylostoma caninum. The origin of several antigens were identified by probing adult A. caninum with mouse monoclonal antibodies (MoAbs), sera from mice vaccinated with ES antigens and sera from human EE patients. Six MoAbs (AC/ES 1-6) were produced against ES antigens, two being IgG3 and four IgM. Western blots demonstrated four different antigen specificities: MoAb AC/ES 1 bound strongly to an ES product at about 30 kDa; AC/ES 2 recognized a broad band ranging from 50-200 kDa; AC/ES 3, AC/ES 5 and AC/ES 6 reacted at about 68 kDa, and AC/ES 4 at about 97 kDa. Sections of formalin-fixed, paraffin embedded adult A. caninum were then incubated with these MoAbs and immunostained by the peroxidase-anti-peroxidase (PAP) technique. The target epitope of MoAb AC/ES 1 was found mainly in the oesophageal, amphidial and excretory glands; AC/ES 2 reacted weakly with many structures in the sections; AC/ES 3, AC/ES 5 and AC/ES 6 were specific for excretory glands only, and AC/ES 4 bound to amphidial glands. Sera from immunized mice reacted with all three (especially the excretory) glands and the cuticle. In an indirect assay, worm sections probes with three human EE patient sera demonstrated maximal staining in the amphidial glands. Our findings confirm that ES products of A. caninum include immunogenic glandular secretions which may be involved in the pathogenesis of human EE.

Ancylostoma↗
PubMed1995

Amplification and characterization of cysteine proteinase genes from nematodes.

In order to isolate proteinase genes from parasitic nematodes by polymerase chain reaction (PCR) techniques, we employed a pair of consensus oligonucleotide primers designed to anneal to the active site cysteine (primer ncpC) and asparagine (primer ncpN) coding regions of cysteine proteinases. The primers were biased toward the nucleotide and codon usages of cysteine proteinase genes of nematodes and were based on the consensus nucleotide sequences flanking the active site residues of genes from Haemonchus contortus, Caenorhabditis elegans, and Ostertagia ostertagi. We employed 'touchdown' PCR conditions and were able to amplify novel cysteine proteinase gene fragments from the rodent parasite Strongyloides ratti, the human pathogen S. stercoralis, the canine hookworm Ancylostoma caninum, and from C. elegans. These clones are gene homologs of cathepsin B-like (lysosomal associated) proteases and will facilitate screening of both cDNA and genomic DNA libraries.

Amino Acid Sequence↗
PubMed1994

Human enteric infection with canine hookworms.

OBJECTIVE: To describe a zoonotic ancylostomiasis (canine), acquired from domestic pets by patients living in developed, urban communities. DESIGN: An 8-year, retrospective case study. SETTING: A clinical gastroenterologic practice in Townsville and a university parasitology department in Brisbane, Australia. PATIENTS: Nine patients, each with enteric hookworm infection diagnosed by finding a single organism in situ; five were treated by us, and the rest were referred to us for parasite identification. MEASUREMENTS: Clinical and demographic data, complete blood examinations, total serum immunoglobulin E assay, and serologic testing with enzyme-linked immunosorbent assay and Western blot using excretory-secretory antigens of Ancylostoma caninum. Gut biopsy specimens were examined histologically, and hookworms were identified using morphologic criteria. RESULTS: The infections in three of the patients were diagnosed during the initial 6 years and six in the last 2 years. All owned a dog and described activity potentially exposing them to infection with canine hookworm larvae. Three patients had a laparotomy for acute abdominal pain, and six had colonoscopies (five with pain and one without symptoms). Six of the nine had blood eosinophilia (mean, 0.97 x 10(9)/L), and five of eight had elevated immunoglobulin E levels (mean level, 756 micrograms/L); six of eight had eosinophilic inflammation of the gut. In six patients, the worm was identified as A. caninum, whereas in three, damage to the specimen did not allow specific identification; however, they were unlikely to be human parasite species. Although all parasites were in the adult stage, none were sexually mature. Positive serologic findings in seven of the eight patients tested confirmed presence of antibody to the parasite. CONCLUSIONS: Human enteric infections with A. caninum are being diagnosed more frequently in northeastern Australia. Although infection may be subclinical, the chief symptom is abdominal pain, sometimes sudden and severe. The pathologic finding is focal or diffuse eosinophilic inflammation caused by a type 1 hypersensitivity response to secreted antigens. Infection by sexually immature worms is scant and nonpatent, indicating poor adaptation to the human host. Serologic testing assists in identification of occult infection. Advanced hygiene and sanitation afford little protection because the parasite reservoir is a large and growing pool of infected domestic pets.

Abdominal Pain↗