Enteropathogen Changes After Rotavirus Vaccine Scale-up

OBJECTIVES

To inform next steps in pediatric diarrhea burden reduction by understanding the shifting enteropathogen landscape after rotavirus vaccine implementation.

METHODS

We conducted a case-control study of 1788 medically attended children younger than 5 years, with and without gastroenteritis, after universal rotavirus vaccine implementation in Peru. We tested case and control stools for 5 viruses, 19 bacteria, and parasites; calculated coinfection-adjusted attributable fractions (AFs) to determine pathogen-specific burdens; and evaluated pathogen-specific gastroenteritis severity using Clark and Vesikari scales.

RESULTS

Six pathogens were independently positively associated with gastroenteritis: norovirus genogroup II (GII) (AF 29.1, 95% confidence interval [CI]: 28.0-32.3), rotavirus (AF 8.9, 95% CI: 6.8-9.7), sapovirus (AF 6.3, 95% CI: 4.3-7.4), astrovirus (AF 2.8, 95% CI: 0.0-4.0); enterotoxigenic Escherichia coli heat stable and/or heat labile and heat stable (AF 2.4, 95% CI: 0.6-3.1), and Shigella spp. (AF 2.0, 95% CI: 0.4-2.2). Among typeable rotavirus cases, we most frequently identified partially heterotypic strain G12P[8] (54 of 81, 67%). Mean severity was significantly higher for norovirus GII-positive cases relative to norovirus GII-negative cases (Vesikari [12.7 vs 11.8; P < .001] and Clark [11.7 vs 11.4; P = .016]), and cases in the 6- to 12-month age range relative to cases in other age groups (Vesikari [12.7 vs 12.0; P = .0002] and Clark [12.0 vs 11.4; P = .0016]).

CONCLUSIONS

Norovirus is well recognized as the leading cause of pediatric gastroenteritis in settings with universal rotavirus vaccination. However, sapovirus is often overlooked. Both norovirus and sapovirus contribute significantly to the severe pediatric disease burden in this setting. Decision-makers should consider multivalent vaccine acquisition strategies to target multiple caliciviruses in similar countries after successful rotavirus vaccine implementation.

Distribution of Capsular Types of Campylobacter jejuni Isolates from Symptomatic and Asymptomatic Children in Peru

Campylobacter jejuni is the leading bacterial cause of diarrhea worldwide. A capsular polysaccharide (CPS) conjugate vaccine is under development and requires determination of the valency. However, distribution of CPS types circulating globally is presently poorly described. We aimed to determine whether CPS type distribution in Peru differs from that in other endemic regions. We used a multiplex polymerase chain reaction (PCR) assay for the detection of CPS encoding genes capable of distinguishing all 35 CPS types on Campylobacter isolates in two prospective communities based studies conducted in cohorts of children less than 59 months of age in Peru. Results showed that CPS type HS4 complex was the most prevalent, followed by HS3 complex and HS15. Differences in CPS type for symptomatology were not statistically significant. Most subjects demonstrated repeated infections over time with different CPS types, suggesting that CPS types may confer of a level of homologous protective immunity. In this dataset, some differences in CPS type distribution were observed in comparison to other low-middle income countries. Further studies need to be conducted in endemic areas to increase our knowledge of CPS type distribution and guide vaccine development.

Methodology of morbidity and treatment data collection in general practice in Australia: a comparison of two methods

OBJECTIVES

To compare two methods of data collection of patient-practitioner encounter data in general practice: from medical records consultation notes and from data recorded on encounter forms.

METHOD

Data were collected from two sources: (i) Medical Records Study: a study of the efficacy of an intervention designed to improve the quality of medical records provided details of 3107 patient encounters with 163 general practitioners (GPs) which had been photocopied from medical records; and (ii) Australian Morbidity and Treatment Survey (AMTS): from a national sample of 495 GPs and over 100,000 patient encounters, data from 47 GPs in the same geographical area as those in the Medical Records Study provided encounter forms for 10,392 patient encounters including details about patient demographics, reason for encounter, management, treatment, tests and investigations, admissions, referrals and planned follow-up. The International Classification of Primary Care (ICPC) was used to code reasons for encounter and problems managed. Drugs were classified according to an in-house classification by generic name and broad drug group.

RESULTS

Patient details and all items of clinical information were recorded less frequently or were more often illegible in medical records than on encounter forms. There was a higher rate of management of problems classified as general or non-specific in the medical records. A lower prescribing rate for drugs acting on the cardiovascular system was recorded in the medical records, but higher rates were found for antibiotics, drugs acting on the immune system and miscellaneous drugs. Coding of all data was more reliable both between and within coders using the data from the encounter forms compared to the medical records.

CONCLUSION

General practice data obtained from encounter forms are more comprehensive and are coded more reliably than those drawn from medical records.

Immunisation in general practice. Results from the Australian Morbidity and Treatment Survey, 1990-1991

Immunisation is the sixth most commonly managed problem in general practice in Australia. This paper provides an overview of its management in general practice.

Development of sample size models for national general practice surveys

The most cost-effective method to measure the morbidity managed and treatments provided in general practice is from records of a cluster of consultations (encounters) from each general practitioner (GP) in a random sample. A cluster sampling method is proposed for future surveys for analysis of encounter-based general practice data. The sample sizes needed to measure the most common problems managed and drugs prescribed were estimated using ratio-estimator models for cluster sample surveys. Morbidity and treatment rates were estimated from the Australian Morbidity and Treatment Survey in General Practice 1990-1991 (AMTS). The 20 most common problems in the AMTS were managed at estimated rates of 1.5 to 9.5 per 100 encounters. The 20 most common drugs were prescribed at estimated rates of 0.7 to 3.6 per 100 problems. These rates were used to determine precision as a percentage of each true value for future surveys, that is, as relative precision. If we want to be 95 per cent confident that these rates will be within 5 per cent of each true rate, sample sizes of 552 to 5675 GPs are needed. If we fix the sample size at 1000 GPs, relative precision lies within 12 per cent of these rates. If the sample size is increased to 1500 GPs, relative precision improves only marginally. The differences in sample size for each of the most frequent morbidity and treatment data are largely due to their variable distributions and relatively infrequent occurrence in general practice. A sample size of 1000 GPs will enable measurement of the most common morbidity and treatments at 95 per cent confidence.

The management of arthritis in general practice. Results from the Australian morbidity and treatment survey, 1990-1991

Arthritis is the ninth most commonly managed problem in general practice in Australia. This paper provides an overview of its management in general practice and draws some comparisons with an earlier study.

The management of osteoarthritis in general practice. Results from the Australian Morbidity and Treatment Survey, 1990-1991

Osteoarthritis is the fourth most commonly managed problem in general practice in Australia. This paper provides an overview of its management in general practice.

Remote sensing as a landscape epidemiologic tool to identify villages at high risk for malaria transmission

A landscape approach using remote sensing and geographic information system (GIS) technologies was developed to discriminate between villages at high and low risk for malaria transmission, as defined by adult Anopheles albimanus abundance. Satellite data for an area in southern Chiapas, Mexico were digitally processed to generate a map of landscape elements. The GIS processes were used to determine the proportion of mapped landscape elements surrounding 40 villages where An. albimanus abundance data had been collected. The relationships between vector abundance and landscape element proportions were investigated using stepwise discriminant analysis and stepwise linear regression. Both analyses indicated that the most important landscape elements in terms of explaining vector abundance were transitional swamp and unmanaged pasture. Discriminant functions generated for these two elements were able to correctly distinguish between villages with high and low vector abundance, with an overall accuracy of 90%. Regression results found both transitional swamp and unmanaged pasture proportions to be predictive of vector abundance during the mid-to-late wet season. This approach, which integrates remotely sensed data and GIS capabilities to identify villages with high vector-human contact risk, provides a promising tool for malaria surveillance programs that depend on labor-intensive field techniques. This is particularly relevant in areas where the lack of accurate surveillance capabilities may result in no malaria control action when, in fact, directed action is necessary. In general, this landscape approach could be applied to other vector-borne diseases in areas where 1) the landscape elements critical to vector survival are known and 2) these elements can be detected at remote sensing scales.

The management of sprains and strains in general practice. Results from the Australian Morbidity and Treatment Survey, 1990-1991

Sprains and strains were the eighth most commonly managed problem in general practice in Australia. This paper provides an overview of their management in general practice.

The management of acute bronchitis in general practice: results from the Australian Morbidity and Treatment Survey, 1990-1991

Acute bronchitis is the fifth most commonly managed problem in general practice in Australia. This paper provides an overview of its management in general practice and compares the results with those of an earlier study.

The management of URTI in general practice. Results from the Australian Morbidity and Treatment Survey, 1990-1991

Upper respiratory tract infection is the second most frequently managed problem in general practice in Australia. This paper provides an overview of its management in general practice and compares the results with those of an earlier study.

The management of hypertension in general practice. Results from the Australian Morbidity and Treatment Survey, 1990-1991

Hypertension is the most frequently managed problem in general practice in Australia. This paper provides an overview of its management in general practice and draws some comparisons with an earlier study.

Dynamics of population densities and vegetation associations of Anopheles albimanus larvae in a coastal area of southern Chiapas, Mexico

Spatial and seasonal variations on Anopheles albimanus larval densities and their plant associations were investigated in larval habitats in southern Mexico between April 1989 and May 1990. Thirty-four plant groups were dominant in larval habitats. Dense larval populations were associated with 3 genera of plants, Cynodon, Echinocloa and Fimbristylis and no larvae were found in habitats with Salvinia and Rhizophora. Low significant positive or negative associations were documented with the other 12 plant genera. Larval habitats were classified according to the morphology of their dominant plants. Higher larval densities were observed in the groups characterized by relatively short emergent vegetation. The distribution of habitat-types within 5 identified vegetation units showed a significantly dependent relationship. For the entire study period, highest larval densities were detected in flooded pasture/grassland vegetation units. For all vegetation units, higher larval densities were found when the dominant plant type covered between 25-50% of the breeding site. The integration of data from habitat-types into vegetation units did not result in loss of information.