Network Of Diagnostic Laboratories Research Articles

Modern clinico-epidemiological features of the course of some communicable infectious zooanthroponous exanthemas in times of war

Objective — to study and analyze modern clinical and epidemiological features of emerging zooanthroponoses, legal and organizational measures to ensure the sanitary and epidemiological well­being of the population of Ukraine in wartime conditions and active hostilities on a large area of the south and east of the country. Materials and methods. An analytical review of a number of scientific publications devoted to the study of zoonotic diseases of the population accompanied by the appearance of exanthems on the skin was carried out. State legislative acts on issues of ensuring sanitary and epidemic welfare of citizens of Ukraine during wartime were also considered. The search for information was carried out in the medical databases PubMed, Elsevier, High Wire Press, Google Scholar for the period 2000—2022 according to the terms of the catalog of medical topics, subject headings with keywords: «dermatozoonosis», «exanthema», «epidemio­logy», «morbidity», «outbreak». Meta-analyses and reviews of relevant literature were studied. The work presents the principles of a scientific approach to the optimization of preventive and anti-epidemic measures to combat infectious zoonotic diseases, which should contribute to the maximally rational use of the laws of classical epidemiology in the conditions of war in order to increase the practical effectiveness of the anti-epidemic and dermatological services of the Ministry of Health of Ukraine.Results and discussion. The complex socio-economic situation of martial law and forced mass resettlement created quite favorable conditions for increasing the incidence of infectious zoonotic diseases in population, including their real outbreaks in certain territories near the front. The article describes methodical and diagnostic approaches, specific epidemiological principles and dermatological criteria for building effective measures to combat zoonotic diseases. A professional justification of the role and place of each of them in various infectious diseases is given, taking into account the provisions of general epidemiology and traditional dermatological semiotics. Conclusions. The principles of mandatory complexity and qualified impact on the main link of the epidemic process are of great importance in the fight against various groups of infectious diseases. Their clinically justified and timely administrative use is necessary to achieve the goals of eradication, elimination and control of infectious diseases. In Ukraine, there is a sufficient normative and legal framework for the proper provision of sanitary and epidemic welfare of the population. In order to prevent the spread of existing or potential infectious agents, in particular emerging pathogens, it is necessary to develop and improve the already existing emergency response plan, particularly, the infrastructure of the health care system, to create a multi-level network of diagnostic laboratories and an integrated system of epidemiological surveillance. It is proposed to increase the branching of the network of institutions capable of identifying pathogens of zoonoses, hospitalization of those who are already sick and persons suspected of having the disease in conditions that will ensure their isolation and proper treatment, and to develop specific recommendations for the prevention of the spread of pathogens with various transmission routes. The task of such centers should be the comprehensiveness of epidemiological, diagnostic and preventive measures which must be carried out professionally and promptly. Also, one of the priorities should be the retraining of doctors of various specialties (epidemiologists, general practitioners — family doctors, dermatologists) on topical issues of zoonoses surveillance.

The Process of Establishing and Managing a Laboratory Diagnostic Network in the COVID-19 Pandemic in Iran

The COVID-19 pandemic caused by the newly emerged coronavirus was first detected in China in December 2019 and rapidly spread worldwide. The rapid spread of the disease urged all countries involved, in accordance with their capacities, take the necessary measures to diagnose and manage the disease. The first patient was diagnosed with COVID-19 in Iran in February 2020. Considering the significant role of the laboratory services in detection and management of the disease, planning and programming to provide access to these services was considered as a top priority for healthcare system in Iran. Adopting all existing laboratory capacities and providing necessary infrastructures for expanding COVID-19 laboratory diagnostics, resulted in the establishment of a nationwide network of COVID-19 molecular diagnostic laboratories within the shortest possible time. In addition to expanding the capacity of laboratory services, improving the laboratory network’s performance have been taken into serious consideration. Despite the strict sanctions, the COVID-19 molecular diagnostic laboratories scaled up to more than 430 laboratories currently (September 2021), mostly are operating in the private sector. With considerable efforts, COVID-19 molecular laboratory network was established to provide nationwide diagnostic services. Considering the capacity for the SARS-CoV-2 Rapid Antigen test, we can now perform more than 100,000 COVID-19 diagnostic tests per day. However, due to the ongoing pandemic and in accordance with the requirements of the health system, it is necessary to plan and carry out more COVID-19 diagnostic tests. This study aimed to introduce the process of establishing the COVID-19 laboratory diagnostic network to manage the COVID-19 pandemic in Iran.

Serotype and genotype diversity of dengue viruses circulating in India: a multi-centre retrospective study involving the Virus Research Diagnostic Laboratory Network in 2018

A retrospective study was undertaken to investigate the circulating dengue virus (DENV) serotypes and genotypes in India in 2018. In total, 4963 samples referred to virus research diagnostic laboratories (n=21), the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV) and ICMR-NIV field units (n=2) for diagnosis of dengue in 2018 were tested using a real-time reverse transcription polymerase chain reaction assay for the presence of DENV serotypes. Representative samples were sequenced for the envelope (E) gene. Regional diversity was observed with regard to the dominant circulating serotypes. DENV-2 was found to be the most common serotype in many states. Thrombocytopenia, petechiae and malaise were associated with DENV-2 infection. Phylogenetic analyses of DENV E gene sequences revealed the circulation of genotypes I and V of DENV-1, two lineages of DENV-2 genotype IV, DENV-3 genotype III and DENV-4 genotype I. This study found regional differences in the prevalence of circulating DENV serotypes in India, and provides baseline data for continuous molecular surveillance. Molecular surveillance may have implications for predicting large-scale outbreaks of dengue if regional shifts in the predominantly circulating serotypes and genotypes are detected during the early phase of the dengue season.

Clinical epigenomics: genome-wide DNA methylation analysis for the diagnosis of Mendelian disorders

PurposeWe describe the clinical implementation of genome-wide DNA methylation analysis in rare disorders across the EpiSign diagnostic laboratory network and the assessment of results and clinical impact in the first subjects tested. MethodsWe outline the logistics and data flow between an integrated network of clinical diagnostics laboratories in Europe, the United States, and Canada. We describe the clinical validation of EpiSign using 211 specimens and assess the test performance and diagnostic yield in the first 207 subjects tested involving two patient subgroups: the targeted cohort (subjects with previous ambiguous/inconclusive genetic findings including genetic variants of unknown clinical significance) and the screening cohort (subjects with clinical findings consistent with hereditary neurodevelopmental syndromes and no previous conclusive genetic findings). ResultsAmong the 207 subjects tested, 57 (27.6%) were positive for a diagnostic episignature including 48/136 (35.3%) in the targeted cohort and 8/71 (11.3%) in the screening cohort, with 4/207 (1.9%) remaining inconclusive after EpiSign analysis. ConclusionThis study describes the implementation of diagnostic clinical genomic DNA methylation testing in patients with rare disorders. It provides strong evidence of clinical utility of EpiSign analysis, including the ability to provide conclusive findings in the majority of subjects tested.

Space time analysis of dengue fever diagnosed through a network of laboratories in India from 2014-2017.

The Department of Health Research and the Indian Council of Medical Research, Government of India, have established Virus Research and Diagnostic Laboratory Network (VRDLN) to strengthen the laboratory capacity in the country for providing timely diagnosis of disease outbreaks. Fifty-one VRDLs were functional as on December 2017 and had reported about dengue fever across Indian states. The objectives of the study were to detect space time clusters and purely temporal clusters of dengue using Kulldorff's SaTScan statistics using patient level information; and to identify regions at greater risk of developing the disease using Kriging technique aggregating at district level. A total of 211,432 patients from 51 VRDLs were investigated for IgM antibodies or NS1 antigen against dengue virus during the period from 1 January 2014 to 31 December 2017 and among them 60,096 (28.4%) were found to be positive. Kulldorff's space time analysis was used to identify significant clusters over space and time. Kriging technique was used to interpolate dengue data for areas not physically sampled using the relationship in the spatial arrangement of the data set. Maps obtained using both the methods were overlaid to identify the regions at greater risk of developing the disease. Kulldorff Space time Scan Statistics using the Bernoulli model with monthly precision revealed eight statistically significant clusters (P <0.001) for the time period, 1 January 2014 to 31 December 2017. Eight significant clusters identified were districts of Nagpur, Jhunjhunu, Gadag, Dakshin Kannada, Kancheepuram, Sivaganga, Ernakulam and Malda. The purely temporal clusters occurred during the last quarter of 2015 and 2016. The Kriging technique identified north eastern part of the country (Arunachal Pradesh, Nagaland and Manipur) and Gujarat. Dengue fever has spread in all directions in the country. Hence, it is need of the hour to perform an in-depth investigation.

Severe acute respiratory illness surveillance for coronavirus disease 2019, India, 2020.

Background & objectives:Sentinel surveillance among severe acute respiratory illness (SARI) patients can help identify the spread and extent of transmission of coronavirus disease 2019 (COVID-19). SARI surveillance was initiated in the early phase of the COVID-19 outbreak in India. We describe here the positivity for COVID-19 among SARI patients and their characteristics.Methods:SARI patients admitted at 41 sentinel sites from February 15, 2020 onwards were tested for COVID-19 by real-time reverse transcription-polymerase chain reaction, targeting E and RdRp genes of SARS-CoV-2. Data were extracted from Virus Research and Diagnostic Laboratory Network for analysis.Results:A total of 104 (1.8%) of the 5,911 SARI patients tested were positive for COVID-19. These cases were reported from 52 districts in 20 States/Union Territories. The COVID-19 positivity was higher among males and patients aged above 50 years. In all, 40 (39.2%) COVID-19 cases did not report any history of contact with a known case or international travel.Interpretation & conclusions:COVID-19 containment activities need to be targeted in districts reporting COVID-19 cases among SARI patients. Intensifying sentinel surveillance for COVID-19 among SARI patients may be an efficient tool to effectively use resources towards containment and mitigation efforts.

A decision-making model for performance evaluation and profit sharing in a diagnostic laboratory network.

Creating networked business models is one of the innovative approaches that have the ability and potential for meeting market needs. The purpose of this study is to provide a decision-making model for a fair profit sharing among the members of a diagnostic laboratory network while providing a distinctive value for the patients. To identify the members of the network of laboratories, a suitable approach to calculate members' efficiency scores is proposed. Then, the network members are classified into three groups based on their performance scores. The three groups help administrators identify eligible members, members who need to improve their performance in order to meet the minimum requirements, and members who do not qualify for admission to the network. Since the performance of the members should play a significant role in the fair profit-sharing mechanism, the fair allocation of profits among network members is done by the use of Shapely value based on the efficiency scores of members. The results show that for such a fair mechanism, the efficiency and sample size (the number of samples [blood and urine] taken from the patients by the laboratories), as the two effective factors, have a decisive role in the share of profit of laboratory units of the network. In the Laboratory Services Network, members receive a number of samples according to their performance. As a result, the sample size received has a direct impact on the net income of each member. In conclusion, it is evident that the use of Shapely value may help managers in the process of sharing profits among network members in a fair way, thereby improving network performance. In this way, incentive strategies may be created for the members of the network, and long-term survival of the network may be achieved.

Salmonella enterica Serovar Napoli Infection in Italy from 2000 to 2013: Spatial and Spatio-Temporal Analysis of Cases Distribution and the Effect of Human and Animal Density on the Risk of Infection.

Background Salmonella Napoli is uncommon in Europe. In Italy however, it has been growing in importance since 2000. To date, no risk factors have been identified to account for its rise. This study aims at describing the epidemiology, spatial and spatio-temporal patterns of S. Napoli in Italy from 2000 to 2013, and to explore the role of several environmental correlates, namely urbanization, altitude and number of livestock farms, on the risk of S. Napoli infection among humans.MethodData were obtained from Enter-Net Italy, a network of diagnostic laboratories. The data were aggregated at the municipality level. Descriptive epidemiology, multivariate regression models, spatial and spatio-temporal analyses were performed on the number of cases and incidence rates.Results S. Napoli showed an expanding trend at the national level, and an increasing number of cases. Compared to the other main serovars in Italy, the risk of S. Napoli infection was higher in the age group <1 year, and lower in the other age groups. Although urbanization and the number of farms were associated with the risk of S. Napoli infection to some extent, their role in the epidemiology of the disease remains inconclusive. S. Napoli cases showed a positive global spatial autocorrelation as well as a significant spatio-temporal interaction. Twenty-four spatial and spatio-temporal clusters were identified, seven purely spatial and 17 spatio-temporal, mainly in north-western Italy. Most of the clusters were in areas characterized by urban and industrial settlements surrounded by agricultural land and an abundance of freshwater bodies.ConclusionsOur results point to the presence, in a number of areas in Italy, of a Salmonella of public health concern originating in the environment. This highlights the increasing relevance of environmental, non-food-related sources of human exposure to enteric pathogens.

Increased frequency of linezolid resistance among clinical Enterococcus faecium isolates from German hospital patients.

Linezolid is an antibiotic of last resort for the treatment of infections with vancomycin-resistant enterococci (VRE). Here we report the increasing prevalence of linezolid resistance among clinical Enterococcus faecium strains from German hospital patients. Linezolid minimum inhibitory concentrations (MICs) were determined for 4461 clinical E. faecium strains isolated between 2008 and 2014. Isolates originated from the network of diagnostic laboratories collaborating with the National Reference Centre (NRC) for Staphylococci and Enterococci covering all German federal states. All linezolid-resistant isolates were determined by broth microdilution and confirmed by Etest as well as by analysing the 23S rDNA for putative mutations. Marker genes were determined by PCR. Genotyping was performed by SmaI macrorestriction analysis in pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) for selected isolates. An increase in linezolid resistance was observed, from <1% in 2008 to >9% in 2014. Occasionally, outbreaks with linezolid-resistant VRE (ST117) were observed. In total, 232 (92.4%) of 251 linezolid-resistant E. faecium isolates (including 61 vanA and 29 vanB) contained the G2576T 23S rDNA mutation and showed a varying mixture of wild-type and mutated alleles per genome sufficient to confer linezolid resistance. In vitro growth experiments revealed a stable linezolid MIC. Of the 251 linezolid-resistant isolates, 5 were cfr-positive. In conclusion, these NRC data identified a country-wide ongoing trend of increasing linezolid resistance among clinical E. faecium isolates within the last 5 years.

Evaluation of commercially available diagnostic tests for the detection of dengue virus NS1 antigen and anti-dengue virus IgM antibody.

Commercially available diagnostic test kits for detection of dengue virus (DENV) non-structural protein 1 (NS1) and anti-DENV IgM were evaluated for their sensitivity and specificity and other performance characteristics by a diagnostic laboratory network developed by World Health Organization (WHO), the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) and the Pediatric Dengue Vaccine Initiative (PDVI). Each network laboratory contributed characterized serum specimens for the panels used in the evaluation. Microplate enzyme-linked immunosorbent assay (ELISA) and rapid diagnostic test (RDT formats) were represented by the kits. Each ELISA was evaluated by 2 laboratories and RDTs were evaluated by at least 3 laboratories. The reference tests for IgM anti-DENV were laboratory developed assays produced by the Armed Forces Research Institute for Medical Science (AFRIMS) and the Centers for Disease Control and Prevention (CDC), and the NS1 reference test was reverse transcriptase polymerase chain reaction (RT-PCR). Results were analyzed to determine sensitivity, specificity, inter-laboratory and inter-reader agreement, lot-to-lot variation and ease-of-use. NS1 ELISA sensitivity was 60–75% and specificity 71–80%; NS1 RDT sensitivity was 38–71% and specificity 76–80%; the IgM anti-DENV RDTs sensitivity was 30–96%, with a specificity of 86–92%, and IgM anti-DENV ELISA sensitivity was 96–98% and specificity 78–91%. NS1 tests were generally more sensitive in specimens from the acute phase of dengue and in primary DENV infection, whereas IgM anti-DENV tests were less sensitive in secondary DENV infections. The reproducibility of the NS1 RDTs ranged from 92-99% and the IgM anti-DENV RDTs from 88–94%.

Scientifically achievable directives: a key driver in the control of transboundary animal diseases

Research can deliver answers to infinite numbers of unsolved questions and provide solutions to problems affecting humankind. Science underpins innovation and technological development, and ultimately provides benefits to humanity. Science, politics, and policy are and should be, the three legs of any country’s legal and regulatory process. Unfortunately, scientists, politicians and policy-decision makers are often disconnected, because research is seen as not being applicable to a particular field or there is a lack of communication and understanding between scientists, investors and stakeholders. The route from science to policy can be complex; however, communication should be early, frequent, and consistent. Communication advocacy and a two-way knowledge sharing is paramount in order to inform policy dialogue, scientific research/advancement and provide useful tools for the future that benefit and is accepted by society. This paper shows three successful examples of the Joint FAO/IAEA (Food and Agriculture Organization of the United Nations/International Atomic Energy Agency) Division of Nuclear Techniques in Food and Agriculture in bringing science to the end-user and decision maker, and highlights the role that policy plays in such endeavours. The first example deals with the worldwide eradication of an animal disease (rinderpest), the second with an African network of diagnostic laboratories of animal diseases in Africa, and the third with international technical support for the control of foot-and-mouth disease in Mongolia. The results show that when approached in an open and motivated environment, unbiased science can indeed make a difference in formulating policy.

Review of laboratory submissions from New World camelids in England and Wales (2000–2011)

Sample submissions to the Animal Health and Veterinary Laboratories Agency’s (AHVLA’s) diagnostic laboratory network in England and Wales were reviewed for diseases affecting New World camelids (NWCs). In the years 2000–2011, 6757 submissions were analysed, including 5154/6757 (76.3%) for diagnosing a disease problem and 1603/6757 (23.7%) for monitoring (no clinical disease). Wasting (weight loss, ill-thrift) was the most commonly reported clinical sign across all age groups. A diagnosis was reached for 1765/5154 (34.2%) diagnostic submissions. The proportion of submissions with diagnoses was higher for carcasses than non-carcass samples and multiple diagnoses were more likely to be reached from carcasses. Parasitic diseases were collectively the most common problem, including parasitic gastroenteritis (319/1765, 18.2%), coccidiosis (187/1765, 10.6%), fascioliasis (151/1765, 8.6%), ectoparasitic infestations (86/1765, 4.9%) and cryptosporidiosis (24/1765, 1.4%). The most frequently diagnosed non-parasitic problems included nutritional diseases (182/1765, 10.3%), septicaemia (104/1765, 5.9%, including 45 cases of colisepticaemia), gastric ulceration (79/1765, 4.5%), tumours/neoplastic diseases (65/1765, 3.7%), tuberculosis (57/1765, 3.2%), clostridial diseases (44/1765, 2.5%), congenital anomalies (41/1765, 2.3%), peritonitis (39/1765, 2.2%) and Johne’s disease (20/1765, 1.1%).

On the implementation of the Biological Threat Reduction Program in the Republic of Uzbekistan

The Biological Threat Reduction Program (BTRP), of the U.S. Defense Threat Reduction Agency, has led to the enhancenment of surveillance activities against a list of especially dangerous pathogens in the Republic of Uzbekistan. BTRP, in partnership with the Ministry of Health of Uzbekistan, has delivered surveillance capability in the form of a network of diagnostic laboratories and epidemiological support units, trainings to surveillance personnel and research projects. The implementation of BTRP within the health care system of the Republic of Uzbekistan has contributed to the stable and sustainable wellbeing of the Uzbek population.

H1N1: A Mexican Perspective

In April this year, a new influenza virus of swine origin emerged in Mexico and spread rapidly around the world. As the Northern hemisphere winter flu season kicks off, Laura Vargas-Parada reports on the measures that Mexico is taking to combat the H1N1 pandemic.

Immunophenotyping of lymphosarcoma in South American camelids on six British premises

Six cases of lymphosarcoma (LSA) in South American camelids (SACs) were selected from submissions to a diagnostic laboratory network servicing England and Wales. Immunophenotyping was carried out using anti-human CD3 and anti-human CD5 for T-cells; and anti-human CD79a and anti-human CD79b for B-cells/plasma cells. On the basis of labelling with mainly anti-CD3, four of the tumours were classified as T-cell tumours. One case was labelled with anti-CD79a and anti-CD79b, and was classified as a B-cell tumour. In the other case the majority of cells were labelled with anti-CD3, anti-CD79a and anti-CD79b, and was classified as a mixed T- and B-cell tumour. To the authors’ knowledge this is the first reported attempt at immunophenotyping LSA in SACs on British premises and is only the second time that a presumptive mixed T- and B-cell LSA has been reported in alpacas and the veterinary literature in general.

Quality control of sputum microscopic examinations for acid fast bacilli in southern Ethiopia

Abstract Background: There has been an ongoing effort to strengthen the acid-fast bacilli (AFB) diagnostic laboratory network in the Southern Region of Ethiopia, and quality control has been initiated as part of this effort. Objective: To evaluate the level of agreement in the readings of sputum smears for AFB between the peripheral diagnostic centers and the reference laboratories. Methods: Blinded rechecking of routine slides collected from the peripheral diagnostic laboratories was undertaken in nine zones of the southern Ethiopian region between October 2000 and June 2002. Results: Two thousand two hundred and nine slides, 54% of which were positive and 46% of which were negative slides, were collected from the peripheral diagnostic centes. Overall, false reading was 3.2% and the overall agreement was 96.8%. Among the 95 discordant slides that were re-examined at the central reference laboratory, 74% were found to be in agreement with the regional laboratory readings while 26% were in agreement with the peripheral readings. Nine zones participated in the quality control activity in 2000, six in 2001 and three in 2002. Conclusion: Good agreement was recorded in the readings of AFB among the peripheral and reference laboratories. However, the false positive reading of 3.2% exceeds the recommended cut-off point of 2%. The number of zones participating decreased from time to time, and there seems to be an urgent need to re-vitalise the quality control initiative. Regular on the job training of the peripheral laboratory staff together with supportive supervision would help improve their performance. [Ethiop.J.Health Dev.2005;19(2):104-108]

Advances in molecular-based diagnostics in meeting crop biosecurity and phytosanitary issues.

Awareness of crop biosecurity and phytosanitation has been heightened since 9/11 and the unresolved anthrax releases in October 2001. Crops are highly vulnerable to accidental or deliberate introductions of crop pathogens from outside U.S. borders. Strategic thinking about protection against deliberate or accidental release of a plant pathogen is an urgent priority. Rapid detection will be the key to success. This review summarizes recent progress in the development of rapid real-time PCR protocols and evaluates their effectiveness in a proposed nationwide network of diagnostic laboratories that will facilitate rapid diagnostics and improved communication.

La organización de los Servicios Veterinarios en Latinoamérica y su evolución

Latin America undoubtedly has comparative advantages in the fields of animal production, animal health and the production of food of animal origin. However, countries in Latin America must build on these strengths if the continent is to become more competitive and be able to deal with the complexities of world markets. To do this, Veterinary Services must define their objectives and establish quality standards on which to base their work. For this to occur, the State must create well-defined regulations, establish systems of audit and find ways of working which allow for a high degree of coordination and collaboration between the public and private sectors. This should be done within a framework of a quality assurance system, which allows for responsible accreditation and independent audit and evaluation. The author discusses the approaches of the different countries in the region to animal health, zoonosis, food safety, veterinary drugs control, animal welfare and export-import control. All programmes relating to these issues must be based on technical information gained through epidemiological surveillance, the network of diagnostic laboratories, quarantine systems, risk analysis, identification and traceability of animals and animal products, registration and control of veterinary drugs, and food safety research. In some countries these systems are already being developed. Maintaining good international relations and cooperating with neighbouring countries is always a challenge for official Veterinary Services and international organisations such as the OIE (World organisation for animal health) have a key role to play in facilitating these relationships.

The contribution of terrestrial sources and sinks to trends in the seasonal cycle of atmospheric carbon dioxide

We characterized decadal changes in the amplitude and shape of the seasonal cycle of atmospheric CO2 with three kinds of analysis. First, we calculated the trends in the seasonal cycle of measured atmospheric CO2 at observation stations in the National Oceanic and Atmospheric Administration Climate Monitoring and Diagnostic Laboratory network. Second, we assessed the impact of terrestrial ecosystems in various localities on the mean seasonal cycle of CO2 at observation stations using the Carnegie‐Ames‐Stanford Approach terrestrial biosphere model and the Goddard Institute for Space Studies (GISS) atmospheric tracer transport model. Third, we used the GISS tracer model to quantify the contribution of terrestrial sources and sinks to trends in the seasonal cycle of atmospheric CO2 for the period 1961–1990, specifically examining the effects of biomass burning, emissions from fossil fuel combustion, and regional increases in net primary production (NPP). Our analysis supports results from previous studies that indicate a significant positive increase in the amplitude of the seasonal cycle of CO2 at Arctic and subarctic observation stations. For stations north of 55°N the amplitude increased at a mean rate of 0.66% yr−1 from 1981 to 1995. From the analysis of ecosystem impacts on the mean seasonal cycle we find that tundra, boreal forest, and other northern ecosystems are responsible for most of the seasonal variation in CO2 at stations north of 55°N. The effects of tropical biomass burning on trends in the seasonal cycle are minimal at these stations, probably because of strong vertical convection in equatorial regions. From 1981 to 1990, fossil fuel emissions contributed a trend of 0.20% yr−1 to the seasonal cycle amplitude at Mauna Loa and less than 0.10% yr−1 at stations north of 55°N. To match the observed amplitude increases at Arctic and subarctic stations with NPP increases, we find that north of 30°N a 1.7 Pg C yr−1 terrestrial sink would be required. In contrast, over regions south of 30°N, even large NPP increases and accompanying terrestrial sinks would be insufficient to account for the increase in high‐latitude amplitudes.

Vibrio mimicus diarrhea following ingestion of raw turtle eggs.

Clinical and epidemiological characteristics of diarrhea associated with Vibrio mimicus were identified in 33 hospitalized patients referred to the Costa Rican National Diagnostic Laboratory Network between 1991 and 1994. The relevant symptoms presented by patients included abundant watery diarrhea, vomiting, and severe dehydration that required intravenous Dhaka solution in 83% of patients but not fever. Seroconversion against V. mimicus was demonstrated in four patients, from whom acute- and convalescent-phase sera were obtained. Those sera did not show cross-reaction when tested against Vibrio cholerae O1 strain VC-12. All the V. mimicus isolates from these cases produced cholera toxin (CT) and were susceptible to commonly used antibiotics. Attempts to isolate this bacterium from stool samples of 127 healthy persons were not successful. Consumption of raw turtle eggs was recalled by 11 of the 19 (58%) individuals interviewed. All but two V. mimicus diarrheal cases were sporadic. These two had a history of a common source of turtle (Lepidochelys olivacea) eggs for consumption, and V. mimicus was isolated from eggs from the same source (a local market). Among the strains, variations in the antimicrobial susceptibility pattern were observed. None of the strains recovered from market turtle eggs nor the four isolates from river water showed CT production. Further efforts to demonstrate the presence of CT-producing V. mimicus strains in turtle eggs were made. Successful results were obtained when nest eggs were tested. In this case, it was possible to isolate CT- and non-CT-producing strains, even from the same egg. For CT detection we used PCR, enzyme-linked immunosorbent assay (ELISA), and Y-1 cell assay, obtaining a 100% correlation between ELISA and PCR results. Primers Col-1 and Col-2, originally described as specific for the V. cholerae O1 ctxA gene, also amplified a 302-bp segment with an identical restriction map from V. mimicus. These results have important implications for epidemiological surveillance in tropical countries where turtle eggs are used for human consumption, serving as potential sources of cholera-like diarrhea.