Wastewater Surveillance for SARS-CoV-2 RNA in Canada

Wastewater surveillance for SARS-CoV-2 RNA is a relatively recent adaptation of long-standing wastewater surveillance for infectious and other harmful agents. Individuals infected with COVID-19 were found to shed SARS-CoV-2 in their faeces. Researchers around the world confirmed that SARS-CoV-2 RNA fragments could be detected and quantified in community wastewater. Canadian academic researchers, largely as volunteer initiatives, reported proof-of-concept by April 2020. National collaboration was initially facilitated by the Canadian Water Network.

Many public health officials were initially skeptical about actionable information being provided by wastewater surveillance even though experience has shown that public health surveillance for a pandemic has no single, perfect approach. Rather, different approaches provide different insights, each with its own strengths and limitations. Public health science must triangulate among different forms of evidence to maximize understanding of what is happening or may be expected. Well-conceived, resourced, and implemented wastewater-based platforms can provide a cost-effective approach to support other conventional lines of evidence. Sustaining wastewater monitoring platforms for future surveillance of other disease targets and health states is a challenge. Canada can benefit from taking lessons learned from the COVID-19 pandemic to develop forward-looking interpretive frameworks and capacity to implement, adapt, and expand such public health surveillance capabilities.

Ethics Guidance for Environmental Scientists Engaged in Surveillance of Wastewater for SARS-CoV-2

The COVID-19 pandemic has given rise to rapid and widespread international pursuit of wastewater surveillance for genetic signals of SARS-CoV-2, the virus causing the pandemic. Environmental scientists and engineers familiar with the techniques required for this endeavor have responded. Many of the environmental scientists engaged in these investigations have not necessarily had experience with the ethical obligations associated with generating and handling human health data. The Canadian Water Network facilitated adoption of these surveillance methods by creating a national coalition, which included a public health advisory group that recognized a need for ethics guidance for the wastewater approach to public health surveillance. This Policy Analysis addresses that need and is based on a review of relevant ethics literature tightly focused on ethics applicable to public health surveillance. That review revealed that classical health bioethics governing clinical practice and general public health ethics guidance did not adequately address key issues in wastewater surveillance. The 2017 World Health Organization guidelines, directly based on a systematic literature review, specifically addressed ethical issues in public health surveillance. The application of relevant ethical guidance to wastewater surveillance is analyzed and summarized for environmental scientists.

Neptune: a bioinformatics tool for rapid discovery of genomic variation in bacterial populations

The ready availability of vast amounts of genomic sequence data has created the need to rethink comparative genomics algorithms using 'big data' approaches. Neptune is an efficient system for rapidly locating differentially abundant genomic content in bacterial populations using an exact k-mer matching strategy, while accommodating k-mer mismatches. Neptune's loci discovery process identifies sequences that are sufficiently common to a group of target sequences and sufficiently absent from non-targets using probabilistic models. Neptune uses parallel computing to efficiently identify and extract these loci from draft genome assemblies without requiring multiple sequence alignments or other computationally expensive comparative sequence analyses. Tests on simulated and real datasets showed that Neptune rapidly identifies regions that are both sensitive and specific. We demonstrate that this system can identify trait-specific loci from different bacterial lineages. Neptune is broadly applicable for comparative bacterial analyses, yet will particularly benefit pathogenomic applications, owing to efficient and sensitive discovery of differentially abundant genomic loci. The software is available for download at: http://github.com/phac-nml/neptune.

Where's the pump? Associating sporadic enteric disease with drinking water using a geographic information system, in British Columbia, Canada, 1996-2005

We investigated whether risk of sporadic enteric disease differs by drinking water source and type using surveillance data and a geographic information system. We performed a cross-sectional analysis, at the individual level, that compared reported cases of enteric disease with drinking water source (surface or ground water) and type (municipal or private). We mapped 814 cases of campylobacteriosis, cryptosporidiosis, giardiasis, salmonellosis and verotoxigenic Escherichia coli infection, in a region of British Columbia, Canada, from 1996 to 2005, and determined the water source and type for each case's residence. Over the 10-year period, the risk of disease was 5.2 times higher for individuals living on land parcels serviced by private wells and 2.3 times higher for individuals living on land parcels serviced by the municipal surface/ground water mixed system, than the municipal ground water system. Rates of sporadic enteric disease potentially differ by drinking water source and type. Geographic information system technology and surveillance data are accessible to local public health authorities and used together are an efficient and affordable way to assess the role of drinking water in sporadic enteric disease.

Feasibility of self-collection of specimens for human papillomavirus testing in hard-to-reach women

To study the feasibility of self-collected specimens for testing human papillomavirus (HPV) status among hard-to-reach women, outreach nurses recruited women in women's centres, shelters and alleys in Vancouver's Downtown Eastside. Of the 151 participants for whom samples were available, 43 (28.5%) tested positive for high-risk HPV. Outreach nurses were able to recontact 81.4% of the participants who tested positive and referred them for further testing. About 14% (21/151) of participants had never received a Papanicolaou smear in British Columbia, as compared with 8.3% (608/7336) of women in the BC general population (p < 0.05). This difference suggests that self-collection of specimens for HPV testing is a feasible method to reach women who have not previously participated in cervical cancer screening programs.

A novel Shigella dysenteriae serovar isolated in Canada

The etiological agent most commonly associated with bacillary dysentery is Shigella. As part of its mandate, the Bacteriology and Enteric Disease Program of Health Canada identifies and serotypes unusual isolates of Shigella received from provincial laboratories of public health. In this report, six unusual isolates from three provinces were analyzed biochemically and serologically using slide and tube agglutinations and molecularly using standard pulsed-filed gel electrophoresis (PFGE), PCR, and PCR-restriction fragment length polymorphism (RFLP) techniques. All six isolates were identical. PFGE analysis grouped these strains; biochemically, they were mannitol negative and consistent with the profile of Shigella. Serologically, these strains produced weak reactions in Shigella dysenteriae serovars 4 and 16 and Escherichia coli O159 and O173 antisera. Molecular serotyping by PCR-RFLP of the rfb gene produced an S. dysenteriae serovar 2/E. coli O112ac pattern. They were positive by PCR for ipaH and ial enteroinvasive genes but negative for all other genes tested. Antiserum was prepared from one of the isolates and tested against Shigella and E. coli reference strains as well as the other isolates. The antiserum reacted with the five remaining isolates and showed cross-reactivity with S. dysenteriae serovars 1, 4, and 16; Shigella flexneri type 3; and E. coli O118, O159, O168, O172, and O173 antigens. Absorbing the sera with E. coli O159 and S. dysenteriae serovar 4 antigen removed all cross-reactions and only slightly reduced the homologous titer. Based on biochemical, molecular, and complete serological analysis, we propose that these six isolates represent a new provisional serovar of S. dysenteriae, type strain BEDP 02-5104.

Outbreak of cyclosporiasis in British Columbia associated with imported Thai basil

Sporadic outbreaks of cyclosporiasis, a common cause of protracted diarrhoea in underdeveloped countries, are often undetected and undiagnosed in industrial countries. In May 2001, an outbreak of Cyclospora cayetanensis gastroenteritis was identified in British Columbia, Canada, with 17 reported cases. We conducted a case-control study involving 12 out of the 17 reported and confirmed case patients. Eleven (92%) of the patients had consumed Thai basil, an essential ingredient in Vietnamese cuisine, compared to 3 out of 16 (19%) of the control patients (P = 0.003). Trace-back investigations implicated Thai basil imported via the United States as the vehicle for this outbreak. This is the first documented sporadic outbreak of cyclosporiasis linked to Thai basil in Canada, and the first outbreak of cyclosporiasis identified in an ethnic immigrant population. This outbreak provides the opportunity to increase our understanding of this emerging pathogen and improve on our prevention and control for future outbreaks.

Epidemiology, antibiotic susceptibility, and serotype distribution of Streptococcus pneumoniae associated with invasive pneumococcal disease in British Columbia - A call to strengthen public health pneumococcal immunization programs

BACKGROUND

This study examined the epidemiology, antibiotic susceptibility and serotype distribution of Streptococcus pneumoniae associated with invasive pneumococcal disease (IPD) in British Columbia.

METHODS

Six hospitals and one private laboratory network participated in a prospective, sentinel laboratory based surveillance study of IPD, between October 1999 and October 2000. At each site, S pneumoniae isolates were collected and epidemiological data were gathered using a structured questionnaire, for all cases of IPD meeting the study case definition. Isolates were serotyped and tested for antimicrobial susceptibility. Bivariate associations were analyzed and multivariate logistic regression was used to identify independent risk factors associated with hospitalization or death.

RESULTS

One hundred three reports and isolates were collected. Seventy-nine per cent of cases were community-acquired, 64% required hospitalization and 5% died. Cases with one or more assessed risk factor for IPD and of female sex were independent variables associated with hospitalization or death. One-third of isolates had reduced penicillin susceptibility and 96% of these represented serotypes contained in the 23-valent pneumococcal polysaccharide vaccine (PPV-23). Overall, 89% of serotypes identified are included in the PPV-23 vaccine and 88% of isolates from children under five years of age are found in the 7-valent pneumococcal conjugate vaccine (PCV-7). Forty-one per cent of cases qualified for publicly funded pneumococcal vaccine and 34% of eligible persons were vaccinated.

CONCLUSIONS

Overall, pneumococcal serotypes associated with IPD in this study closely matched serotypes included in PPV-23 products currently licensed in Canada. Most serotypes associated with IPD in children under five years of age are included in a recently licenced PCV-7. One third of isolates demonstrated reduced penicillin susceptibility, most involving serotypes included in PPV-23. Effective delivery of current public health immunization programs using PPV-23 and extending protection to infants and young children using the PCV-7 will prevent many cases of IPD.

Evaluation of a diagnostic polymerase chain reaction assay for Neisseria meningitidis in North America and field experience during an outbreak

CONTEXT

Meningococcal infection has a high public profile because of its dramatic presentation, high fatality rate, and propensity to occur in outbreaks and clusters of cases. Use of a diagnostic polymerase chain reaction (PCR) assay could enhance laboratory confirmation of cases and guide the public health response in North America.

OBJECTIVE

To assess the performance of a PCR assay for the diagnosis of meningococcal disease after its implementation in a North American setting and to evaluate sensitivity and specificity of the assay for the detection of prevalent bacterial isolates.

DESIGN

Laboratory evaluation of the sensitivity and specificity of a PCR assay for Neisseria meningitidis and observational study of a series of cases comparing molecular diagnosis against the criterion standard of conventional laboratory diagnostic tests.

SETTING

A Canadian province with a population of 4 million people.

PATIENTS

Children and adults presenting with suspected meningococcal disease in British Columbia.

MAIN OUTCOME MEASURES

The sensitivity and specificity of the PCR assay when compared against standard laboratory methods.

RESULTS

The PCR assay correctly identified all of 38 Canadian isolates of Neisseria meningitidis and correctly assigned the serogroup to each isolate. None of 57 other gram-positive or gram-negative bacteria or yeasts were detected by the PCR assay. In a clinical evaluation, for diagnosis of meningococcal disease, the PCR assay had a sensitivity and specificity of 91% and 76%, respectively, against conventional methods of diagnosis. Use of the PCR assay increased the laboratory confirmation of clinically suspected cases by 36%. During an outbreak, the PCR assay allowed serogroup determination in 3 of 7 cases, aiding in the public health decision to launch an immunization campaign.

CONCLUSIONS

The PCR assay is more sensitive than conventional methods for the diagnosis of meningococcal disease, and enhanced surveillance may help direct the public health response to the changing epidemiology of disease in North America.

Enzyme immunoassay detection of antigen-specific immunoglobulin g antibodies in longitudinal serum samples from patients with cryptosporidiosis

Cryptosporidium parvum is a protozoan parasite that causes diarrheal illness in a wide range of mammalian hosts, including humans. Characteristic serum immunoglobulin G (IgG) antibody responses to antigens in the 27- and 17-kDa size ranges have been shown to develop after infection, and several enzyme-linked immunosorbent assay (ELISA) and Western blot assay formats have been used to measure these IgG levels in human serum. Using a collection of serial samples from laboratory-confirmed cryptosporidiosis patients, we compared the results obtained by using two new ELISAs with those obtained with two different Western blot assays. When assayed with the large-format Western blot, 97% of the 67 patients had a demonstrable antibody response on at least one occasion. The Cp23 ELISA correctly identified 93% of the samples that had a 27-kDa response by Western blot and 100% of the negative samples. The Triton antigen ELISA detected 77% of the samples that had a 17-kDa response by Western blot and 88% of the negative samples. The sensitivity of the Triton antigen assay was higher for samples collected between 16 and 92 days after the onset of symptoms (96%). The minigel-format Western blot did not compare favorably with the large-format blot for the detection of antibodies to the 27-kDa antigen (71% sensitivity). A half-life of about 12 weeks was estimated for antibodies to both the 27- and 17-kDa antigens. We believe the Cp23 and Triton antigen ELISAs will be useful in epidemiologic studies of the prevalence of Cryptosporidium infection in the population.

Epidemic and endemic seroprevalence of antibodies to Cryptosporidium and Giardia in residents of three communities with different drinking water supplies

This study was carried out to compare cryptosporidiosis and giardiasis seroprevalence rates in residents of three communities. Community (Com 1) uses drinking water from deep wells, community 2 (Com 2) uses surface water from a protected watershed, and community 3 (Com 3) uses surface water frequently containing Cryptosporidium oocysts and Giardia cysts. Unfiltered drinking water from each community was collected at the tap and tested for Cryptosporidium oocysts and Giardia cysts during the 12 months in which sera were collected for testing. No oocysts or cysts were detected in the water from the Com 1 deep wells; oocysts and cysts were detected intermittently in the drinking water from the other two communities. A waterborne outbreak of cryptosporidiosis occurred in a municipality adjacent to Com 3 six months into this 12-month study. Sera from residents of each of the communities were collected proportionately by month and by population size. Coded sera were tested for IgG to Cryptosporidium using a previously developed Western blotting method. The presence or absence of bands at 15-17 kD and/or 27 kD was recorded for the 1,944 sera tested. Definite bands at 15-17 kD and/or 27 kD were detected in 981 (50.5%) of the sera. A total of 33.2% of sera from Com 1 (community using deep wells) were positive using the same criteria compared with 53.5% (Com 2) and 52.5% (Com 3) of sera from the two communities using surface drinking water. Both bands (15-17 kD plus 27 kD) were detected in 582 sera (29.9%) from the three communities: 14.1% of sera from Com 1 compared with 32.7% from Com 2 and 31.5% from Com 3. These findings are consistent with a lower risk of exposure to Cryptosporidium from drinking water obtained from deep well sources. However, analysis of results by calendar quarter showed a significant (P < 0.001) increase in the number of Com 3 positive sera (compared with Com 1) following the waterborne outbreak. Without this outbreak-related observation, a significant overall difference in seropositivity would not have been seen. We also observed that in sera from the community affected by the outbreak, the presence on immunoblots of both Cryptosporidium bands appeared to be the best indicator of recent infection. Seroprevalence rates using an ELISA to detect IgG to Giardia were estimated using the same sera. Overall 30.3% (590 of 1,944) of sera were positive by the ELISA. A total of 19.1% of sera from Com 1, 34.7% from Com 2 and 16.0% from Com 3 were seropositive. Rates for both Com 3 and Com 1 did not change significantly over time. In Com 2, rates decreased significantly (P < 0.001) during the last half of the study period (third and fourth calendar quarters). The reasons for the decrease in seroprevalence in Com 2 sera are presently not known. These studies show intriguing associations between seroprevalence, outbreak-related laboratory serologic data, and patterns of parasite contamination of drinking water. Further studies are required to validate the serologic approach to risk assessment of waterborne parasitic infections at a community level.

Multiple cases of acquired toxoplasmosis retinitis presenting in an outbreak

OBJECTIVE

The purpose of the study was to examine the variability in presentation and outcome of individuals presenting with acquired toxoplasmosis retinitis in the setting of an outbreak of the disease.

DESIGN

The study design was a case series.

PARTICIPANTS

Twenty-one eyes of 20 patients with equal gender distribution and a mean age of 54 years followed for 38 to 170 weeks (mean 113.7 weeks) were studied.

INTERVENTION

Systemic antimicrobials and corticosteroids when indicated were given.

MAIN OUTCOME MEASURES

Visual acuity, media inflammation and clarity, resolution of active retinitis, and appearance of recurrence were observed.

RESULTS

Fifteen of 21 lesions were active, and 7 of the total number of lesions fell within the macula-peripapillary region. Overall, vision improved with treatment except in cases of macular involvement (3 cases) and persistent vitritis (3 cases). Four recurrences have occurred to date.

CONCLUSIONS

This is the largest reported outbreak of acquired toxoplasmosis retinitis occurring within a single outbreak. Twenty-one eyes of 20 patients presented with retinal lesions, and on average, those treated for active retinitis had improvement in vision.

Detection of Toxoplasma gondii oocysts in drinking water

The world's largest outbreak of waterborne toxoplasmosis occurred in a municipality in the western Canadian province of British Columbia. When drinking water emerged as a possible source of infection during the outbreak investigation, a laboratory method was needed to attempt detection of the parasite, Toxoplasma gondii. The method developed was based on the current U.S. Environmental Protection Agency method for detection of Cryptosporidium oocysts. Collection of large-volume drinking water samples and cartridge filter processing were unchanged, although identification of Toxoplasma oocysts in the filter retentate was carried out by using a previously described rodent model. Validation of the method developed was tested by using oocysts from a well-characterized Toxoplasma strain.

Studies of Giardia spp. and Cryptosporidium spp. in two adjacent watersheds

Two adjacent British Columbia, Canada, watersheds with similar topographical features were studied. Both the Black Mountain Irrigation District (BMID) and the Vernon Irrigation District (VID) serve rural agricultural communities which are active in cattle ranching. The present study was carried out in five phases, during which a total of 249 surface water samples were tested in the study watersheds. The aims of these phases were to determine levels of parasite contamination in raw water samples collected from the intakes as well as from other sites in each watershed and to investigate cattle in the watersheds as potential sources of parasite contamination of surface drinking water supplies. Giardia cysts were not detected in the raw water samples collected from lake sources at the headwaters of both watersheds but were found in 100% (70 or 70) of water samples collected at the BMID intake and 97% (68 of 70) of water samples collected at the VID intake. Significantly higher levels (P < 0.05) of Giardia cysts were found at the BMID intake (phase 1, 7 to 2,215 cysts per 100 liters; phase 3, 4.6 to 1,880 cysts per 100 liters) when compared with that of the VID intake (2 to 114 cysts per 100 liters). The BMID watershed has a more complex system of surface water sources than the VID watershed. Cattle have access to creeks in the BMID watershed, whereas access is restricted in the VID watershed. Collection of raw water samples from a creek upstream and downstream of a cattle ranch in the BMID watershed showed that the downstream location had significantly higher (P < 0.05) levels (0.6 to 42.9 cysts per 100 liters and 1.4 to 300.0 oocysts per 100 liters) of both Giardia cysts and Cryptosporidium oocysts than those of the upstream location (0.5 to 34.4 cysts per 100 liters and 0.5 to 34.4 oocysts per 100 liters). Peak concentrations of both parasites coincided with calving activity. Fecal samples, collected from cattle in both watersheds, showed 10% (3 of 30) in the BMID and 50% (5 of 10) in the VID watersheds to be Giardia positive. No Cryptosporidium-positive fecal samples were found. Giardia cysts isolated from the BMID watershed were repeatedly infective to gerbils in contrast to those from the VID watershed. The 10 BMID drinking water Giardia isolates retrieved into culture and biotyped showed zymodeme and karyotype heterogeneity. The differences in patterns of parasite contamination and cattle management practices contribute to the unique watershed characteristics observed between two areas which are topographically similar and geographically adjacent.

The molecular epidemiology of Giardia lamblia: a sequence-based approach

Animals are commonly considered to be potential sources for Giardia lamblia infections in humans, but the extent of zoonotic transmission of G. lamblia remains controversial because of inadequate understanding of its epidemiology. A better understanding of the epidemiology of G. lamblia may be facilitated by a more effective means for classifying G. lamblia isolates. To develop a sequence-based classification system, the gene encoding the metabolic enzyme triose phosphate isomerase (tim) was sequenced from a number of G. lamblia isolates of various host origins. Restriction enzymes were identified that can distinguish among isolates without the need for sequencing, simplifying the application of this approach to the epidemiologic investigation of giardiasis. Isolates from a previously reported epidemic of giardiasis were accurately classified by this technique, further verifying its utility for epidemiologic investigation.

Longitudinal studies of Giardia contamination in two community drinking water supplies: cyst levels, parasite viability, and health impact

Giardia cyst concentrations were determined in an inventory of 153 raw and 91 chlorinated drinking water samples collected at 86 sites from throughout the western Canadian province of British Columbia. Sixty-four percent of raw water samples were cyst positive (69% of sites). Cyst concentrations were lower in chlorinated than in raw water. The viability of cysts in drinking water samples assessed by infectivity in Mongolian gerbils (Meriones unguiculatus) was decreased in chlorinated water. Two rural communities using Giardia-contaminated surface drinking water sources were selected for longitudinal studies including drinking water testing and serological studies of residents. Three hundred thirty-six raw and treated samples from these communities were collected over 24 months. Cyst concentrations and viability were assessed in a 12-month study of each community. Parasite concentrations were lower in chlorinated water than in raw water in both communities. Cyst concentrations were lower in reservoir-settled water than in raw water. Viability, assessed by animal infectivity and corrected for inoculum, decreased following reservoir settling as well as after chlorination. A bolus or spiking phenomenon of cysts was observed in both community drinking water systems and deserves further study. A striking seasonal pattern was seen in one community but not in the second. The seroprevalence data and number of laboratory-confirmed cases identified in each year-long community study are consistent with the possibility that low-level endemic transmission is occurring.

Pulsed-field gel electrophoresis as a method of biotyping of Giardia duodenalis

Pulsed-field gel electrophoresis (PFGE) has allowed karyotypic characterization of protozoa at a species and a subspecies level. Different methods of PFGE have been applied to analysis of Giardia isolates from the major morphologic groups and of isolates from the G. duodenalis group. We developed a four-day method of contour-clamped homogeneous electric field PFGE that produced reliable chromosomal band separation for isolates from the G. duodenalis group. When a significant waterborne outbreak of giardiasis occurred in a town in British Columbia, this biotyping method was assessed by characterization of isolates associated with the outbreak. Results were compared with karyotypes obtained from isolates retrieved in other parts of the province, as well as with reference isolates. Isolates in this study were found to have 4-6 chromosomal bands estimated to be between 1 and 4 Mb in size. The chromosomal complement of the outbreak-associated isolates was relatively homogeneous and distinguishable from the non-outbreak-associated British Columbia and reference isolates. The present study showed this PFGE method to be useful in biotyping isolates of G. duodenalis. This study also exemplifies the degree of heterogeneity displayed at the genotypic level of Giardia, as well as the apparent stability of the outbreak-associated karyotype during transmission from original infecting animal through a water vehicle to human cases.

Review of human and animal cases of coccidioidomycosis diagnosed in Canada

The first Canadian case of coccidioidomycosis in a human was reported in 1952 and 11 more cases since then. This study provides details of other cases of coccidioidomycosis that have been diagnosed in Canada. Based on clinical details, isolation of Coccidioides immitis, detection of a specific antibody (F band) for coccidioidomycosis by macro- or microimmunodiffusion tests, concurrently used with the complement fixation procedure, and histopathological findings, 116 more cases of this disease were verified. The great majority (94%) of these cases were diagnosed in the western Canadian provinces of British Columbia, Alberta, Saskatchewan and Manitoba, and the others in Quebec, Ontario and Nova Scotia (5, 1, and 1 cases, respectively). Available information indicates that the C. immitis infections were contracted during visits to endemic areas in the United States (Arizona, California and New Mexico), Mexico, and Bolivia. Pulmonary infections were the most common type of coccidioidomycosis (93%) followed by the disseminated or meningeal types C. immitis infections occurred in individuals with or without predisposing factor(s) and were more common in males than in females. The exoantigen procedure was very useful and reliable in the accurate and rapid identification of suspected C. immitis isolates. Two cases of coccidioidomycosis were reported in animals in Ontario, Canada.

Immunoblot patterns of Giardia duodenalis isolates from different hosts and geographical locations

Eighteen isolates of Giardia duodenalis from animal and human sources were studied for protein differences by polyacrylamide gel electrophoresis and for antigenic differences by immunoblot analysis. The polyacrylamide gels showed that whilst the isolates were for the most part homogeneous in their protein banding patterns, some isolates did show some differences. The immunoblot analysis yielded many bands, including prominent bands of 32 and 66 kilodaltons. Five of the six isolates that showed differences in protein banding pattern also showed differences in antigenic reactivity. Our findings suggest that differences can be seen with the use of immunoblotting and that this technique is a tool that may be useful for isolate differentiation when used in conjunction with other techniques.

Endemic institutional strongyloidiasis in British Columbia

The incidental finding in 1984 of Strongyloides stercoralis larvae in a resident of a chronic care institution who had a vague clinical illness prompted a review of the other residents. Five other cases were identified after exhaustive laboratory investigations. Fecal-oral spread was considered the most likely manner of the spread of infection. The possibility of endemic strongyloidiasis in institutions should be considered, even in temperate climates, when there is unexplained persistent illness or high eosinophil counts. Serologic testing is a useful adjunct to fecal examination in such situations.

Campylobacter infections in pregnancy. Case report and literature review

Campylobacter fetus is a major cause of venereally transmitted abortion and sterility in ungulates, and a recently recognized, common enteric pathogen in man. The role of the organism as a cause of human fetal wastage has not been delineated. We present a case of bacteremic campylobacter infection in a pregnant woman, and review the published cases of campylobacteriosis in pregnancy and the perinatal period. Systemic maternal infection may present either as prolonged febrile illness or fulminant sepsis, and transplacental spread may result in abortion, stillbirth, or early neonatal meningitis. Enteritis that occurs in infants born to women with campylobacter diarrhea may represent fecal-oral spread at or near the time of delivery. With improved microbiologic techniques and greater awareness by physicians, the prevalence and importance of campylobacteriosis in pregnancy should become better appreciated.