Exposure to Toxoplasma gondii and cat ownership in Nova Scotia.

In this survey, 998 children and adolescents between 7 months and 17 years of age who attended a hospital diagnostic center in the city of Halifax, Nova Scotia, for routine evaluation were tested for Toxoplasma gondii antibody. The 5.2% prevalence rate of antibody for children living in the outlying rural areas was significantly higher than the 1.1% rate among the urban children (P = .0006). Seroprevalence increased with age for both rural and urban children. Cat ownership was associated with antibodies to Toxoplasma among rural children but not urban children. Rural children who lived in a house with more than one cat were two times more likely to be infected than children who had one cat and three times more likely to be infected than children with no cats. The geometric mean titer was also significantly higher among the rural children with more than one cat, 1:152, than rural children with one or no cats, 1:63 (P = .02). In light of these findings for children and adolescents, the association of Toxoplasma infection with cat ownership needs to be thoroughly evaluated among pregnant women in rural areas.

Prevalence of human immunodeficiency virus in the patient population of a sexually transmitted disease clinic. Association with syphilis and gonorrhea.

An unlinked seroprevalence survey of human immunodeficiency virus (HIV) antibody was conducted using stored sera from all patients who attended the sexually transmitted disease (STD) clinic in Halifax, Nova Scotia between 1980 and 1986. None of the sera collected from 584 patients during 1980 were HIV positive. Of the 2867 patients who visited the clinic between 1981 and 1986, 27 (0.9%; 95% CI 0.6% to 1.2%) had the antibody. None of the 784 female patients were HIV seropositive. Of the 1,884 heterosexual men in the study, 5 (0.3%; 95% CI 0.1% to 0.5%) were HIV seropositive, and 22 (11.1%; 95% CI 6.7% to 15.5%) of the 199 homosexual men were HIV seropositive. There was a strong association between a history of syphilis and HIV antibody among heterosexual men (OR = 76.8; 95% CI 12.0 to 491.3; P = 0.001). Among homosexual men younger than 30 years of age, HIV infection was associated with a history of syphilis (OR = 18.2; 95% CI 5.1 to 64.7; P = 0.035) and a history of gonorrhea (OR = 8.2; 95% CI 4.2 to 16.0; P = 0.001). The association between a history of gonorrhea and HIV infection was strongest among homosexual men who had three or more sexual partners in the last month. These findings supplement existing evidence that STDs increase the likelihood of HIV transmission.

A seroepidemiologic study of cytomegalovirus infection in a Canadian recruit population.

The prevalence of antibodies to cytomegalovirus (CMV) was investigated in a population of Canadian male and female military recruits entering a basic-training session in Nova Scotia. Of 660 incoming recruits, 119 (18.0%) had IgG and/or IgM antibodies to CMV detectable by a latex agglutination procedure. There was no statistically significant difference between the prevalence of CMV antibodies among male recruits (16.2%) and that among female recruits (21.8%) (p = .085). The prevalence of antibodies to CMV in this recruit population is similar to that in the general Canadian population. During the 8- to 10-week training session, 1.7% of the recruits (.8% of the males and 3.6% of the females) seroconverted to become seropositive for antibodies to CMV. There was some equivocal evidence that the females had a higher CMV seroconversion rate than did the males (p = .030). There was no significant difference between the geometric mean titers of the male and female recruits who seroconverted. This seroconversion rate suggests that CMV transmission was low during the training session even though physical crowding was present.

Herpes simplex virus infection: what to look for. What to do!

Herpes simplex virus (HSV) is a ubiquitous microorganism that is highly prevalent in the general population. This prevalence and the oral manifestations put dentists, dental hygienists and dental patients at risk of being accidentally infected with HSV. This brief review highlights some of the basic properties of HSV, its transmission and pathogenesis. As well, common HSV oral infections are reviewed and suggestions are put forward to prevent the accidental transmission of HSV.

Cytomegalovirus infection among women attending a sexually transmitted disease clinic: association with clinical symptoms and other sexually transmitted diseases.

The prevalence rates of cytomegalovirus, Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, and herpes simplex virus infection were determined for 247 women attending a sexually transmitted disease clinic in Halifax, Nova Scotia between July 1983 and December 1985. Isolation rates were 8.5%, 32.8%, 27.1%, 7.3%, and 6.5% for the five infectious agents, respectively. With multiple logistic regression analysis, the presence of cervical cytomegalovirus infection was independently associated with age less than 23 years and with gonococcal infection. Factors predictive of C. trachomatis infection included age less than 23 years, gonococcal infection, oral contraceptive use, and purulent discharge. Number of lifetime sexual partners was statistically associated only with herpes simplex virus infection. N. gonorrhoeae, C. trachomatis, and T. vaginalis were all independently associated with purulent discharge. Cytomegalovirus, N. gonorrhoeae, and C. trachomatis were statistically more likely to be present concurrently with other organisms than to be present as a single infection. Women with another genital infection were 6.5 times more likely to have cytomegalovirus than were women with no other genital infection. Of the 21 women with cytomegalovirus, only two had no other sexually transmitted disease. These findings suggest that N. gonorrhoeae and other sexually transmitted diseases may play a role in either the sexual transmission of or the reactivation of cervical cytomegalovirus infection.

Prevalence of antibody to Toxoplasma gondii in the moose (Alces alces americana Clinton) of Nova Scotia, Canada.

The prevalence of antibodies to Toxoplasma gondii was investigated in the sera of 125 moose taken by hunters in 5 countries of Nova Scotia. Nineteen of these sera (15%) were positive by the indirect passive hemagglutination test, with titers above 1:64. This study adds further evidence to the prevalence of antibodies to T. gondii in the wildlife, extending this evidence to eastern Canada. The possibility that humans may acquire toxoplasmosis by ingesting undercooked infected meat from game animals is supported by the results of this investigation; the implications of these findings to public health are obvious.

Herpes simplex virus infections in male and female mice following pinna inoculation: responses to primary infection and artificially induced recurrent disease.

The pathogenesis of herpes simplex virus (HSV) infection is now well understood. After humans or experimental animals recover from primary infection, the virus remains latent in sensory ganglia of the peripheral nervous system. Latency, for the most part, remains unresolved, and elucidating the mechanisms involved with latency has proved difficult. The requirement for unravelling HSV latency is the availability of a reproducible animal model. Previously, the mouse ear model has been extensively characterized; however, many studies using this model have involved female mice only despite evidence that recurrent HSV infection in humans may vary by gender. We inoculated male and female mice subcutaneously in the pinna with varying amounts of one of four strains of HSV and monitored the mice for signs of primary infection. Following recovery from primary infection, mice were induced to develop recurrent disease. In addition, we attempted to isolate virus from dorsal root ganglia of mice suspected of harboring latent virus. There were no differences in the response of male and female mice to either primary infection or artificially induced recurrent disease when inoculated with the same virus. Differences were noted when female mice were inoculated with different strains of virus.

Hepatitis A: a serological study in the Canadian Armed Forces.

Sera were collected from 3958 Canadian Forces personnel, including recruits, personnel posted to bases in Canada and on rotation with United Nations Peacekeeping forces, and the crew of a Canadian destroyer. All sera were tested for the presence of anti-hepatitis A antibodies by a competitive radioimmunoassay. The overall prevalence of anti-hepatitis A antibodies was found to be 23.5% (3.2% to 40.0%). The incidence of viral hepatitis A, as measured by seroconversion in paired sera, was found to be 0.17% (0.01% to 1.42%). The study results support the existence of a direct relationship between increasing age and an increased prevalence of anti-hepatitis A antibodies.

Association of oral candidiasis with diabetic control.

Factors associated with oral candidiasis in 51 diabetics were examined. The prevalence of oral yeast infection was 49 (n = 25)%. The association with diabetic control, as measured by fasting blood glucose concentration, urinary glucose concentration, and glycosylated haemoglobin, with the presence of yeast was analysed in the 51 diabetic patients. Glycosylated haemoglobin above 12% was strongly associated with oral yeast infection (odds ratio = 13.00) (p less than 0.001), while fasting blood and urinary glucose concentrations were not. The risk of oral candidiasis among diabetics wearing dentures was significantly higher than among dentate diabetics (odds ratio = 4.78). After controlling for the effect of denture wearing, glycosylated haemoglobin greater than 12% remained highly predictive of oral yeast infection, particularly among diabetics without dentures.

In vitro effect of ivermectin on Pseudoterranova decipiens survival.

Third larval stages (L3) removed from fish fillets, fourth larval stages (L4) raised in in vitro culture, and adults of Pseudoterranova decipiens, collected from grey seal (Halichoerus grypus) stomachs, were exposed to the broad spectrum anthelmintic, ivermectin. L3 and L4 parasites were exposed, in vitro, to 500, 100, 50, 20, 5 and 1 micrograms/ml concentrations of the drug, in culture media. Adult P. decipiens were exposed in vitro to a concentration of 500 micrograms/ml ivermectin, only. Controls consisted of parasites placed in culture media alone or culture media plus drug vehicle. These three developmental stages of P. decipiens were all found to be susceptible to the effects of ivermectin.

Apparent stability of herpes simplex virus genomes isolated from primary and recurrent infections and dorsal root ganglia in the mouse.

Following natural or experimental primary infection, herpes simplex virus (HSV) becomes latent in sensory ganglia. Reactivation of latent virus may lead to recurrent disease. If HSV DNA remains stable during primary, recurrent and latent infections, that stability would enable us to trace the transmission of HSV from one individual to another. We inoculated mice in the ear pinna with HSV and collected virus at various intervals during primary infection. In mice surviving primary infections, recurrent disease was induced from which virus was isolated. Virus was also recovered from explanted dorsal root ganglia. Virus isolates were characterised by restriction endonuclease digestion and compared with the original inoculate(s). The data indicate that in all cases except two, the isolates from primary and recurrent infections remained identical to the original inoculates.

Levels of cytomegalovirus seropositivity in homosexual and heterosexual men.

The prevalence of antibodies to cytomegalovirus (CMV) among 57 homosexual men (77.2%) was significantly higher than that among 155 heterosexual men (32.3%) attending a sexually transmitted disease clinic. The difference in prevalences was most pronounced in those under 30 years of age. No difference in CMV seroprevalence was observed between the heterosexual patients and a control group of blood donors. The geometric mean titer of seropositive homosexuals (1:79) was significantly higher than that of heterosexuals (1:28) in both younger and older age groups. These data suggest that homosexual men are exposed to CMV at a much earlier age than heterosexuals and that homosexuals experience frequent reactivation or reinfection with CMV.

Prevalence of lower genital tract infections in pregnancy.

A descriptive profile of 106 pregnant women with various forms of cervicitis and vaginitis is provided. Fifty women attending individual physicians' private offices are compared with 56 clinic patients: 34 attending a university prenatal teaching clinic and 22 attending a pregnancy termination unit. Univariate analysis showed that single women were significantly more likely to be infected by mycoplasmas, yeasts, trichomonads, and Gardnerella vaginalis than were married women. Teenagers were more frequently infected by Mycoplasma hominis, yeasts, and Trichomonas vaginalis than were women older than 20 years. After stepwise logistic regression analysis, the most significant predictor of infection with M. hominis, Ureaplasma urealyticum, or yeasts was being a clinic patient; for G. vaginalis, the most significant variable was being unmarried. These data suggest that teenaged and single women who are pregnant will benefit most from routine screening for vaginitis/cervicitis-producing microorganisms.

Gastrointestinal parasitic infections.

This article surveys the most important gastrointestinal parasites that affect humans. The modes of acquisition, pathology, epidemiology, diagnosis, and treatment are all briefly examined. Gastrointestinal parasites have become increasingly important in the differential diagnosis of gastrointestinal disease, as a result of a number of circumstances. These circumstances include: increasing travel to developing countries; increased numbers, for one reason or another, of immunocompromised individuals; increased consumption of raw or partially cooked ethnic delicacies; more crowding in day-care centres; increased immigration from developing countries; and an endemic pocket of individuals with certain unhygienic or unsanitary practices.

Prolonged excretion of an identical cytomegalovirus strain by two siblings and the intermittent isolation of an adenovirus from the urine of one of them.

Restriction endonucleases were used to show the excretion of an identical strain of cytomegalovirus (CMV) by two brothers over a 2 1/2-yr period. The same enzymes were used to show that the younger brother, case report, excreted an adenovirus over at least a 3-mo period. We are unable to determine the contribution of each virus to this child's clinical picture; however, this is the first report of a prolonged excretion of an adenovirus associated with CMV excretion in an immunocompetent host.

Visualization of replicating herpes simplex virus in cervical dorsal root ganglia of mice following explant of individual ganglion onto susceptible indicator cells.

Herpes simplex virus (HSV) establishes a latent state in the sensory ganglia of the peripheral nervous system of its natural or experimental host following primary infection. At various times thereafter, the virus can be reactivated from the latent state whereby it migrates back to the periphery and sometimes initiates a clinical syndrome referred to as recurrent disease. We inoculated mice in the right ear pinna and, following recovery from primary infection, killed the mice at various intervals following either the presence or absence of peripheral stimulations. Explanted cervical dorsal root ganglia yielded HSV in culture and was positive for HSV-like virus particles when viewed with the electron microscope. Hematoxylin and eosin staining showed neuron degeneration, and corresponding HSV-specific immunoperoxidase stains were also positive. The data indicate that ganglionic cells are capable of supporting replicating HSV and that, in vitro, numerous ganglionic cells can be infected simultaneously.