Leveraging PEPFAR-Supported Health Information Systems for COVID-19 Pandemic Response

Since 2003, the US President's Emergency Plan for AIDS Relief (PEPFAR) has supported implementation and maintenance of health information systems for HIV/AIDS and related diseases, such as tuberculosis, in numerous countries. As the COVID-19 pandemic emerged, several countries conducted rapid assessments and enhanced existing PEPFAR-funded HIV and national health information systems to support COVID-19 surveillance data collection, analysis, visualization, and reporting needs. We describe efforts at the US Centers for Disease Control and Prevention (CDC) headquarters in Atlanta, Georgia, USA, and CDC country offices that enhanced existing health information systems in support COVID-19 pandemic response. We describe CDC activities in Haiti as an illustration of efforts in PEPFAR countries. We also describe how investments used to establish and maintain standards-based health information systems in resource-constrained settings can have positive effects on health systems beyond their original scope.

Health information exchange policy and standards for digital health systems in africa: A systematic review

Lack of interoperability and integration between heterogeneous health systems is a big challenge to realize the potential benefits of eHealth. To best move from siloed applications to interoperable eHealth solutions, health information exchange (HIE) policy and standards are necessary to be established. However, there is no comprehensive evidence on the current status of HIE policy and standards on the African continent. Therefore, this paper aimed to systematically review the status of HIE policy and standards which are currently in practice in Africa. A systematic search of the literature was conducted from Medical Literature Analysis and Retrieval System Online (MEDLINE), Scopus, Web of Science, and Excerpta Medica Database (EMBASE), and a total of 32 papers (21 strategic documents and 11 peer-reviewed papers) were selected based on predefined criteria for synthesis. Results revealed that African countries have paid attention to the development, improvement, adoption, and implementation of HIE architecture for interoperability and standards. Synthetic and semantic interoperability standards were identified for the implementation of HIE in Africa. Based on this comprehensive review, we recommend that comprehensive interoperable technical standards should be set at each national level and should be guided by appropriate governance and legal frameworks, data ownership and use agreements, and health data privacy and security guidelines. On top of the policy issues, there is a need to identify a set of standards (health system standards, communication, messaging standards, terminology/vocabulary standards, patient profile standards, privacy and security, and risk assessment) and implement them throughout all levels of the health system. On top of this, we recommend that the Africa Union (AU) and regional bodies provide the necessary human resource and high-level technical support to African countries to implement HIE policy and standards. To realize the full potential of eHealth in the continent, it is recommended that African countries need to have a common HIE policy, interoperable technical standards, and health data privacy and security guidelines. Currently, there is an ongoing effort by the Africa Centres for Disease Control and Prevention (Africa CDC) towards promoting HIE on the continent. A task force has been established from Africa CDC, Health Information Service Provider (HISP) partners, and African and global HIE subject matter experts to provide expertise and guidance in the development of AU policy and standards for HIE. Although the work is still ongoing, the African Union shall continue to support the implementation of HIE policy and standards in the continent. The authors of this review are currently working under the umbrella of the African Union to develop the HIE policy and standard to be endorsed by the head of states of the Africa Union. As a follow-up publication to this, the result will be published in mid-2022.

Rapid reduction of maternal mortality in Uganda and Zambia through the saving mothers, giving life initiative: results of year 1 evaluation

Background

Achieving maternal mortality reduction as a development goal remains a major challenge in most low-resource countries. Saving Mothers, Giving Life (SMGL) is a multi-partner initiative designed to reduce maternal mortality rapidly in high mortality settings through community and facility evidence-based interventions and district-wide health systems strengthening that could reduce delays to appropriate obstetric care.

Methods

An evaluation employing multiple studies and data collection methods was used to compare baseline maternal outcomes to those during Year 1 in SMGL pilot districts in Uganda and Zambia. Studies include health facility assessments, pregnancy outcome monitoring, enhanced maternal mortality detection in facilities, and population-based investigation of community maternal deaths. Population-based evaluation used standard approaches and comparable indicators to measure outcome and impact, and to allow comparison of the SMGL implementation in unique country contexts.

Results

The evaluation found a 30% reduction in the population-based maternal mortality ratio (MMR) in Uganda during Year 1, from 452 to 316 per 100,000 live births. The MMR in health facilities declined by 35% in each country (from 534 to 345 in Uganda and from 310 to 202 in Zambia). The institutional delivery rate increased by 62% in Uganda and 35% in Zambia. The number of facilities providing emergency obstetric and newborn care (EmONC) rose from 10 to 25 in Uganda and from 7 to 11 in Zambia. Partial EmONC care became available in many more low and mid-level facilities. Cesarean section rates for all births increased by 23% in Uganda and 15% in Zambia. The proportion of women with childbirth complications delivered in EmONC facilities rose by 25% in Uganda and 23% in Zambia. Facility case fatality rates fell from 2.6 to 2.0% in Uganda and 3.1 to 2.0% in Zambia.

Conclusions

Maternal mortality ratios fell significantly in one year in Uganda and Zambia following the introduction of the SMGL model. This model employed a comprehensive district system strengthening approach. The lessons learned from SMGL can inform policymakers and program managers in other low and middle income settings where similar approaches could be utilized to rapidly reduce preventable maternal deaths.

Rapidly building global health security capacity--Uganda demonstration project, 2013

Increasingly, the need to strengthen global capacity to prevent, detect, and respond to public health threats around the globe is being recognized. CDC, in partnership with the World Health Organization (WHO), has committed to building capacity by assisting member states with strengthening their national capacity for integrated disease surveillance and response as required by International Health Regulations (IHR). CDC and other U.S. agencies have reinforced their pledge through creation of global health security (GHS) demonstration projects. One such project was conducted during March-September 2013, when the Uganda Ministry of Health (MoH) and CDC implemented upgrades in three areas: 1) strengthening the public health laboratory system by increasing the capacity of diagnostic and specimen referral networks, 2) enhancing the existing communications and information systems for outbreak response, and 3) developing a public health emergency operations center (EOC) (Figure 1). The GHS demonstration project outcomes included development of an outbreak response module that allowed reporting of suspected cases of illness caused by priority pathogens via short messaging service (SMS; i.e., text messaging) to the Uganda District Health Information System (DHIS-2) and expansion of the biologic specimen transport and laboratory reporting system supported by the President's Emergency Plan for AIDS Relief (PEPFAR). Other enhancements included strengthening laboratory management, establishing and equipping the EOC, and evaluating these enhancements during an outbreak exercise. In 6 months, the project demonstrated that targeted enhancements resulted in substantial improvements to the ability of Uganda's public health system to detect and respond to health threats.

Threshold survey evaluating transmitted HIV drug resistance among public antenatal clinic clients in Addis Ababa, Ethiopia

Background

Expanded access to HIV therapy in the developing world raises serious concerns regarding the potential emergence and transmission of drug-resistant HIV strains. Although HIV drug resistance surveillance is recommended to track transmitted HIV drug resistance among newly infected individuals, the financial constraints in resource-limited countries prohibit such surveillance on a regular basis. The World Health Organization (WHO) recently introduced guidelines to address this issue.

Methods

A survey was conducted in Ethiopia following the WHO guidelines to assess transmitted HIV drug resistance among recently HIV-infected individuals in Addis Ababa. Antiretroviral drug usage started 3 years earlier than commencement of the current expanded access to antiretroviral therapy in Ethiopia.

Results

Of 75 eligible samples, 39 (52%) were successfully sequenced and genotyped in the protease and reverse transcriptase region, using both the ViroSeq® and TrueGene® genotyping systems, and analysed for drug resistance mutations using an algorithm from the Stanford HIV Reverse Transcriptase and Protease Database. The analysis revealed that transmitted HIV drug resistance in Addis Ababa is below the 5% threshold level for all three classes of antiretrovirals.

Conclusions

The current first-line antiretroviral therapy strategy can be used with confidence in Ethiopia at this time; however, Ethiopia should conduct similar periodic surveys that include the capitals of Ethiopia's larger regional states to ensure early detection of any changes in the country's HIV drug resistance trend.

Threshold survey evaluating transmitted HIV drug resistance among public antenatal clinic clients in Addis Ababa, Ethiopia

BACKGROUND

Expanded access to HIV therapy in the developing world raises serious concerns regarding the potential emergence and transmission of drug-resistant HIV strains. Although HIV drug resistance surveillance is recommended to track transmitted HIV drug resistance among newly infected individuals, the financial constraints in resource-limited countries prohibit such surveillance on a regular basis. The World Health Organization (WHO) recently introduced guidelines to address this issue.

METHODS

A survey was conducted in Ethiopia following the WHO guidelines to assess transmitted HIV drug resistance among recently HIV-infected individuals in Addis Ababa. Antiretroviral drug usage started 3 years earlier than commencement of the current expanded access to antiretroviral therapy in Ethiopia.

RESULTS

Of 75 eligible samples, 39 (52%) were successfully sequenced and genotyped in the protease and reverse transcriptase region, using both the ViroSeq and TrueGene genotyping systems, and analysed for drug resistance mutations using an algorithm from the Stanford HIV Reverse Transcriptase and Protease Database. The analysis revealed that transmitted HIV drug resistance in Addis Ababa is below the 5% threshold level for all three classes of antiretrovirals.

CONCLUSIONS

The current first-line antiretroviral therapy strategy can be used with confidence in Ethiopia at this time; however, Ethiopia should conduct similar periodic surveys that include the capitals of Ethiopia's larger regional states to ensure early detection of any changes in the country's HIV drug resistance trend.

Assessment of the implementation of HIV-rapid test kits at different levels of health institutions in Ethiopia

OBJECTIVE

Evaluation and monitoring of Human Immunodeficiency Virus (HIV) testing reagents at the point of service is helpful to prevent the occurrence of problems related to testing and interpretation. To evaluate the implementation of HIV rapid test kits at the point of services in voluntarily counseling and testing (VCT) and diagnostic centers in Ethiopia.

METHODS

The assessment was the third phase of evaluation of HIV rapid test kits in Ethiopia followed from phase-I and phase-II. Known proficiency testing panels, well-structured questionnaire (addressing type of tests, human resource and problems related to tests), onsite supervision and retesting of samples collected from sites were used to evaluate the performances of reagents and laboratories.

RESULTS

Forty-four health institutions were included. Thirty-six (90.0%) health institutions had trained human resource on HIV testing. In 27 (61.4%) three types of HIV rapid test kits (Determine, Capillus and Unigold) were available. Serial-algorithm was used in all the laboratories. In 31 (70.4%) of them external quality control specimens were not used. Twenty two (50.0%) of the laboratories reported frequent shortage of reagents. All (100%) were able to identify negative specimens distributed. Positive proficiency panel samples were identified in 37 (94.8%) of the 39 laboratories. There was 98.3% agreement at a screening level between the sites and the central laboratory. Rate of discrepancy between screening and confirmatory assays was found to be 3.0% and 2.1% at the sites and at central laboratory, respectively.

CONCLUSION

The test kits showed a good performance at the point of services in the field sites. However, continuous assessment of HIV test kits at the point of service and training of professionals on newly arrived techniques are recommended to have effective testing performance with acceptable sensitive and specific testing algorithm. Effective quality assurance program should be in place to support programs such as VCT, prevention of mother-to-child-transmission and antiretroviral therapy.

Temporal trends in the incidence of HIV infection in antenatal clinic attendees in Addis Ababa, Ethiopia, 1995-2003

BACKGROUND

The HIV incidence data are relevant in depicting the current dynamics and trend of the epidemic. Using a new laboratory method for HIV-1 incidence, we aimed at estimating a 10-year trend in HIV-1 incidence in Addis Ababa, Ethiopia.

METHODS

We determined the temporal trends in HIV incidence based on a total of 7744 serum specimens from pregnant women who attended antenatal clinics in Addis Ababa between 1995 and 2003. HIV incidence was determined by IgG-capture HIV-1 BED incidence enzyme immunoassay following a validation using a well-characterized panel of serial serum specimens from subtype C-infected seroconverters.

FINDINGS

Of the 1350 HIV+ specimens tested as part of the annual sentinel survey between 1995 and 2003, a total of 1332 (98.7%) were tested by BED HIV-1 incidence assay. The incidence rate of HIV-1 infection declined significantly from 7.7% (95% CI, 3.9-11.5%) in 1995 to 2.0% (95% CI, 0.7-3.3%) in 2003. Although there was a trend, amongst the age group of 15-29 years, in age-specific decline in incidence, it was not statistically significant. No change in HIV incidence rate was observed for the group aged above 30 years.

INTERPRETATION

A corresponding decline in the incidence of HIV infection was observed with the decline in the prevalence of HIV infection between 1995 and 2003 in Addis Ababa City. Whether the declines were because of changes in sexual behaviours or other reasons needs to be explored. The BED HIV-1 incidence assay provides a valuable tool in obtaining information on recent HIV-1 infection.

Evaluation of rapid HIV test kits on whole blood and development of rapid testing algorithm for voluntary testing and counseling centers in Ethiopia

Five simple and rapid HIV antibody detection assays viz. Determine, Capillus, Oraquick, Unigold and Hemastrip were evaluated to examine their performance and to develop an alternative rapid test based testing algorithm for voluntary counseling and testing (VCT) in Ethiopia. All the kits were tested on whole blood, plasma and serum. The evaluation had three phases: Primary lab review, piloting at point of service and implementation. This report includes the results of the first two phases. A total of 2,693 specimens (both whole blood and plasma) were included in the evaluation. Results were compared to double Enzyme Linked Immuno-Sorbent Assay (ELISA) system. Discordant EIA results were resolved using Western Blot. The assays had very good sensitivities and specificities, 99-100%, at the two different phases of the evaluation. A 98-100% result agreement was obtained from those tested at VCT centers and National Referral Laboratory for AIDS (NRLA), in the quality control phase of the evaluation. A testing strategy yielding 100% [95% CI; 98.9-100.0] sensitivity was achieved by the sequential use of the three rapid test kits. Direct cost comparison showed serial testing algorithm reduces the cost of testing by over 30% compared to parallel testing in the current situation. Determine, Capillus/Oraquick (presence/absence of frefrigeration) and Unigold were recommended as screening, confirmation and tiebreaker tests, respectively.

Underestimation of infant mortality rates in one republic of the former Soviet Union

OBJECTIVES

Kazakhstan's live-birth definition--that dates from the former Soviet Union (FSU) era--differs from that used by the World Health Organization (WHO). We studied the impacts of both live-birth definitions on the computations of the infant mortality rate (IMR) and maternal and child health (MCH) planning in Zhambyl Oblast, Kazakhstan.

METHODS

We interviewed caregivers and abstracted medical records to obtain birth weight and age-at-death information on infant deaths in Zhambyl Oblast from November 1, 1996, through October 31, 1997. Using the 2 indicators of birth weight and age at death, we created a matrix delineating the respective contribution to infant death (maternal health, newborn care, or infant care) for the cells. We then calculated the IMR, birth weight-specific IMR (BWS-IMR), and birth weight-proportionate IMR (BWP-IMR) for each cell.

RESULTS

The observed IMR in Zhambyl Oblast, in 1996--using the definition of a live birth from the FSU--was 32 per 1000 live births. The recalculated IMR--using the WHO definition--was 58.7 per 1000 live births. Computed estimates of the contribution to infant death, by the categories of maternal health, newborn care, and infant care, were 10%, 23%, and 67%, respectively, when using the live-birth definition from the Soviet era. These estimates shifted to 24%, 41%, and 35%, respectively, when using the WHO definition, yet only 8% of the Zhambyl Oblast MCH budget was earmarked to maternal health and newborn care, which we estimated accounted for 65% of infant deaths.

CONCLUSIONS

The live-birth definition commonly used in the FSU underestimated the IMR and undervalued the contributions to infant death by both maternal health and newborn care. We recommend that all republics of the FSU adopt the WHO live-birth definition so that the IMR can serve as a better indicator for MCH planning.

Assessment of the infectious diseases surveillance system of the Republic of Armenia: an example of surveillance in the Republics of the former Soviet Union

BACKGROUND

Before 1991, the infectious diseases surveillance systems (IDSS) of the former Soviet Union (FSU) were centrally planned in Moscow. The dissolution of the FSU resulted in economic stresses on public health infrastructure. At the request of seven FSU Ministries of Health, we performed assessments of the IDSS designed to guide reform. The assessment of the Armenian infectious diseases surveillance system (AIDSS) is presented here as a prototype.

DISCUSSION

We performed qualitative assessments using the Centers for Disease Control and Prevention (CDC) guidelines for evaluating surveillance systems. Until 1996, the AIDSS collected aggregate and case-based data on 64 infectious diseases. It collected information on diseases of low pathogenicity (e.g., pediculosis) and those with no public health intervention (e.g., infectious mononucleosis). The specificity was poor because of the lack of case definitions. Most cases were investigated using a lengthy, non-disease-specific case-report form Armenian public health officials analyzed data descriptively and reported data upward from the local to national level, with little feedback. Information was not shared across vertical programs. Reform should focus on enhancing usefulness, efficiency, and effectiveness by reducing the quantity of data collected and revising reporting procedures and information types; improving the quality, analyses, and use of data at different levels; reducing system operations costs; and improving communications to reporting sources. These recommendations are generalizable to other FSU republics.

SUMMARY

The AIDSS was complex and sensitive, yet costly and inefficient. The flexibility, representativeness, and timeliness were good because of a comprehensive health-care system and compulsory reporting. Some data were questionable and some had no utility.

Conceptual framework of public health surveillance and action and its application in health sector reform

BACKGROUND

Because both public health surveillance and action are crucial, the authors initiated meetings at regional and national levels to assess and reform surveillance and action systems. These meetings emphasized improved epidemic preparedness, epidemic response, and highlighted standardized assessment and reform.

METHODS

To standardize assessments, the authors designed a conceptual framework for surveillance and action that categorized the framework into eight core and four support activities, measured with indicators.

RESULTS

In application, country-level reformers measure both the presence and performance of the six core activities comprising public health surveillance (detection, registration, reporting, confirmation, analyses, and feedback) and acute (epidemic-type) and planned (management-type) responses composing the two core activities of public health action. Four support activities - communications, supervision, training, and resource provision - enable these eight core processes. National, multiple systems can then be concurrently assessed at each level for effectiveness, technical efficiency, and cost.

CONCLUSIONS

This approach permits a cost analysis, highlights areas amenable to integration, and provides focused intervention. The final public health model becomes a district-focused, action-oriented integration of core and support activities with enhanced effectiveness, technical efficiency, and cost savings. This reform approach leads to sustained capacity development by an empowerment strategy defined as facilitated, process-oriented action steps transforming staff and the system.

Persistent diarrhea signals a critical period of increased diarrhea burdens and nutritional shortfalls: a prospective cohort study among children in northeastern Brazil

Persistent diarrhea (PD; duration >/=14 days) is a growing part of the global burden of diarrheal diseases. A 45-month prospective cohort study (with illness, nutritional, and microbiologic surveillance) was conducted in a shantytown in northeastern Brazil, to elucidate the epidemiology, nutritional impact, and causes of PD in early childhood (0-3 years of age). A nested case-control design was used to examine children's diarrhea burden and nutritional status before and after a first PD illness. PD illnesses accounted for 8% of episodes and 34% of days of diarrhea. First PD illnesses were preceded by a doubling of acute diarrhea burdens, were followed by further 2.6-3.5-fold increased diarrhea burdens for 18 months, and were associated with acute weight shortfalls. Exclusively breast-fed children had 8-fold lower diarrhea rates than did weaned children. PD-associated etiologic agents included Cryptosporidium, Giardia, enteric adenoviruses, and enterotoxigenic Escherichia coli. PD signals growth shortfalls and increased diarrhea burdens; children with PD merit extended support, and the illness warrants further study to elucidate its prevention, treatment, and impact.

Longitudinal study of Cryptosporidium infection in children in northeastern Brazil

A prospective, 4-year cohort study of children born in an urban slum in northeastern Brazil was undertaken to elucidate the epidemiology of Cryptosporidium infection in an endemic setting, describe factors associated with Cryptosporidium-associated persistent diarrhea, and clarify the importance of copathogens in symptomatic cryptosporidiosis. A total of 1476 episodes of diarrhea, accounting for 7581 days of illness (5.25 episodes/child-year), were recorded: of these, 102 episodes (6.9%) were persistent. Cryptosporidium oocysts were identified in 7.4% of all stools, and they were found more frequently in children with persistent diarrhea (16.5%) than in those with acute (8.4%) or no (4.0%) diarrhea (P<.001). Low-birth-weight children and those living in densely crowded subdivisions were at greater risk for symptomatic infection. Disease course was highly variable and was not associated with the presence of copathogens. Recurrent Cryptosporidium infection and relapsing diarrhea associated with it were moderately common. In light of these data, the applicability of the current World Health Organization diarrheal definitions to Cryptosporidium-associated diarrheal episodes may need to be reconsidered.

Cryptosporidiosis in northeastern Brazilian children: association with increased diarrhea morbidity

To evaluate the impact of Cryptosporidium infection on diarrheal disease burden and nutrition status, a nested case-control study was done among children who were followed from birth in Fortaleza, Brazil. The diarrhea history and growth records of 43 children with a symptomatic diarrhea episode of cryptosporidiosis (case-children) were compared with those of 43 age-matched controls with no history of cryptosporidiosis. After Cryptosporidium infection, case-children < or = 1 year old experienced an excessive and protracted (nearly 2 years) diarrheal disease burden. Case-children < or = 1 year old with no history of diarrhea prior to their Cryptosporidium infection also experienced a subsequent increased diarrheal disease burden with an associated decline in growth. Control subjects experienced no change in their diarrhea burden over time. This study suggests that an episode of symptomatic Cryptosporidium infection in children < or = 1 year of age is a marker for increased diarrhea morbidity.

Seroepidemiology of Entamoeba histolytica in a slum in northeastern Brazil

Infection with the human pathogenic parasite Entamoeba histolytica has not been well-characterized in northeastern Brazil. In this study, the prevalence of E. histolytica infection in a slum in northeastern Brazil was assayed using an enzyme-linked immunosorbent assay (ELISA) for antibodies against the galactose/N-acetyl-D-galactosamine (Gal/GalNAc)-inhibitable adherence lectin of E. histolytica. Sera from a total of 335 individuals were examined for anti-Gal/GalNAc lectin antibodies. The overall seropositivity was 24.7%; 29.4% of females and 19.4% of males were positive. Among different age groups there was a peak of 40% positivity in the 6-14-year-old age group. There was also familial clustering of seropositivity. To examine colonization, stool samples from 155 people were examined microscopically for the presence of the parasite. Fourteen of 155 stools (9.0%) were identified as containing E. histolytica or nonpathogenic E. dispar. These 14 positive stools were analyzed with an ELISA that detects Gal/GalNAc lectin antigen and can distinguish between E. histolytica and E. dispar. Four stools (29%) were positive for E. histolytica and the remaining 10 were identified as E. dispar-positive. Although the overall colonization rate by microscopy was only 9%, with a third identified as E. histolytica, up to 40% of older children develop serologic evidence of having experienced pathogenic E. histolytica infection. The results of this study demonstrate that this community in northeastern Brazil is highly endemic for E. histolytica with infection rates similar to other developing nations.

Cryptosporidial and microsporidial infections in human immunodeficiency virus-infected patients in northeastern Brazil

To determine the frequency of the parasitic pathogens in human immunodeficiency virus (HIV)-infected patients in a developing world setting, 295 stool specimens were examined from 166 HIV-positive patients (49% with AIDS) at São José Hospital, Fortaleza, Brazil, from September 1990 to March 1992. Significantly more patients with diarrhea (85%) than without (66%) had AIDS or AIDS-related complex (ARC) (P < .005). Of the potential parasitic causes of diarrhea, only Cryptosporidium parvum and microsporidia were significantly associated with diarrheal disease. Infections with C. parvum, but not microsporidia, were associated with the rainy season (P < .005). Thus, C. parvum and microsporidia are the most common intestinal parasites associated with diarrhea in an HIV-infected population in Brazil and are associated with advanced HIV disease. The association of C. parvum infections with the rainy season suggests that contaminated water may be important in its transmission; however, the source of human microsporidia requires further investigation.

Household epidemiology of Cryptosporidium parvum infection in an urban community in northeast Brazil

OBJECTIVE

To examine the transmission of Cryptosporidium infection in households with an identified person with cryptosporidiosis.

DESIGN

Prospective cohort study.

SETTING

An urban slum in Fortaleza, Brazil.

PARTICIPANTS

Thirty-one households with a child less than 3 years of age (index case) who was positive for Cryptosporidium parvum using acid-fast and auramine-stained stool smears.

MEASUREMENTS

Three stool samples (at 0, 2, and 6 weeks after identification of the index case) and two serum samples (0 and 6 weeks) were collected from each family member in households with an index case of Cryptosporidium infection.

RESULTS

Forty-five percent of index cases of Cryptosporidium infection were associated with persistent (> 14 days) diarrhea. Secondary cases of Cryptosporidium infection were identified either by stool examination or seroconversion in 18 (58%) of 31 households involving 30 persons, yielding an overall transmission rate of 19%. Of the 202 persons in this study with at least one serum sample available for analysis, 191 (94.6%) had evidence of antibodies (either IgM or IgG) to Cryptosporidium.

CONCLUSIONS

Cryptosporidium parvum is highly transmissible and infective in the family setting, with transmission rates similar to other highly infectious enteric pathogens such as Shigella species. These data are cause for added concern because of the rapidly increasing rate of seropositivity for human immunodeficiency virus.

Environmental sources of Cryptosporidium in an urban slum in northeastern Brazil

Cryptosporidium is an important cause of diarrheal disease in children worldwide. To elucidate the environmental sources of this parasite, we selected an urban slum in Fortaleza, Brazil, a community with a known high incidence of cryptosporidiosis, and examined both stool smears from household animals (n = 127) and filtrates from local water sources (n = 18) for Cryptosporidium oocysts. Because previous work in this community has demonstrated the seasonal nature of human infection with Cryptosporidium, collections were made separately for the dry and rainy seasons. Of the 64 stools collected during the dry season (September-December 1990), four (6.3%) were positive by acid-fast staining for Cryptosporidium. Of the 63 rainy season samples (March-May 1991), nine (14.3%) were positive. Overall, oocysts were detected in 13 (10.2%) of 127 animal stool samples. Freshwater samples were obtained from a variety of sources including open and closed wells, and running city water and then processed. Four of 18 samples (22.2%), including a sample from city water were positive by at least one of two staining techniques (acid-fast and immunofluorescence). In summary, animals may serve as a reservoir of Cryptosporidium, with potential for the contamination of immediate household water sources. These findings may help to explain the high incidence of cryptosporidiosis among infants in this impoverished community.

Evaluation of an antigen capture enzyme-linked immunosorbent assay for detection of Cryptosporidium oocysts

The diagnosis of the small (4- to 6-microns) Cryptosporidium oocysts is labor intensive and relies on stool concentration, with subsequent staining and microscopy. The primary purpose of this study was to evaluate the clinical utility of an antigen capture enzyme-linked immunosorbent assay (ELISA) (LMD Laboratories, Carlsbad, Calif.) in detecting Cryptosporidium oocysts in human stools. A total of 591 specimens (76 diarrheal, 515 control) obtained from 213 inhabitants of an urban slum in northeastern Brazil were examined by both ELISA and conventional microscopic examination (CME) of formalin-ethyl acetate-concentrated stool samples stained with modified acid-fast and auramine stains. Forty-eight diarrheal stools (63.2%) were positive for Cryptosporidium oocysts by CME, with 40 of these positive by ELISA. Thirty-five control stools (6.8%) had Cryptosporidium oocysts detected by CME, with 15 of these also positive by ELISA. All of the 480 nondiarrheal stools and all but one of the diarrheal stools negative by CME were negative by ELISA. The test had an overall sensitivity of 66.3% and a specificity of 99.8% (positive predictive value, 98.2%; negative predictive value, 94.8%). In the evaluation of human diarrheal stool samples, the test sensitivity increased to 83.3%, with a specificity of 96.4%, and, in analysis of samples from individual patients with diarrhea, the sensitivity was 87.9%, with a specificity of 100%. These results indicate that this stool ELISA is sensitive and specific for the detection of Cryptosporidium oocysts in human diarrheal stool specimens but has limited use in epidemiologic studies for the diagnosis of asymptomatic Cryptosporidium infection.