Associating Land Cover Changes with Patterns of Incidences of Climate-Sensitive Infections: An Example on Tick-Borne Diseases in the Nordic Area

Some of the climate-sensitive infections (CSIs) affecting humans are zoonotic vector-borne diseases, such as Lyme borreliosis (BOR) and tick-borne encephalitis (TBE), mostly linked to various species of ticks as vectors. Due to climate change, the geographical distribution of tick species, their hosts, and the prevalence of pathogens are likely to change. A recent increase in human incidences of these CSIs in the Nordic regions might indicate an expansion of the range of ticks and hosts, with vegetation changes acting as potential predictors linked to habitat suitability. In this paper, we study districts in Fennoscandia and Russia where incidences of BOR and TBE have steadily increased over the 1995-2015 period (defined as 'Well Increasing districts'). This selection is taken as a proxy for increasing the prevalence of tick-borne pathogens due to increased habitat suitability for ticks and hosts, thus simplifying the multiple factors that explain incidence variations. This approach allows vegetation types and strengths of correlation specific to the WI districts to be differentiated and compared with associations found over all districts. Land cover types and their changes found to be associated with increasing human disease incidence are described, indicating zones with potential future higher risk of these diseases. Combining vegetation cover and climate variables in regression models shows the interplay of biotic and abiotic factors linked to CSI incidences and identifies some differences between BOR and TBE. Regression model projections up until 2070 under different climate scenarios depict possible CSI progressions within the studied area and are consistent with the observed changes over the past 20 years.

Toxoplasma gondii-specific IgG avidity testing in pregnant women

BACKGROUND

The parasite Toxoplasma gondii can cause congenital toxoplasmosis following primary infection in a pregnant woman. It is therefore important to distinguish between recent and past infection when both T. gondii-specific IgM and IgG are detected in a single serum in pregnant women. Toxoplasma gondii-specific IgG avidity testing is an essential tool to help to date the infection. However, interpretation of its results can be complex.

OBJECTIVES

To review the benefits and limitations of T. gondii-specific avidity testing in pregnant women, to help practitioners to interpret the results and adapt the patient management.

SOURCES

PubMed search with the keywords avidity, toxoplasmosis and Toxoplasma gondii for articles published from 1989 to 2019.

CONTENT

Toxoplasma gondii-specific IgG avidity testing remains a key tool for dating a T. gondii infection in immunocompetent pregnant women. Several commercial assays are available and display comparable performances. A high avidity result obtained on a first-trimester serum sample is indicative of a past infection, which occurred before pregnancy. To date, a low avidity result must still be considered as non-informative to date the infection, although some authors suggest that very low avidity results are highly suggestive of recent infections depending on the assay. Interpretation of low or grey zone avidity results on a first-trimester serum sample, as well as any avidity result on a second-trimester or third-trimester serum sample, is more complex and requires recourse to expert toxoplasmosis laboratories.

IMPLICATIONS

Although used for about 30 years, T. gondii-specific avidity testing has scarcely evolved. The same difficulties in interpretation have persisted over the years. Some authors have proposed additional thresholds to exclude an infection of <9 months, or in contrast to confirm a recent infection. Such thresholds would be of great interest to adapt management of pregnant women and avoid unnecessary treatment; however, they need confirmation and further studies.

Identifying climate-sensitive infectious diseases in animals and humans in Northern regions

BACKGROUND

General knowledge on climate change effects and adaptation strategies has increased significantly in recent years. However, there is still a substantial information gap regarding the influence of climate change on infectious diseases and how these diseases should be identified. From a One Health perspective, zoonotic infections are of particular concern. The climate in Northern regions is changing faster than the global average. This study sought to identify climate-sensitive infectious diseases (CSIs) of relevance for humans and/or animals living in Northern regions. Inclusion criteria for CSIs were constructed using expert assessments. Based on these principles, 37 potential CSIs relevant for Northern regions were identified. A systematic literature search was performed in three databases using an explicit stepwise approach to determine whether the literature supports selection of these 37 potential CSIs.

RESULTS

In total, 1275 nominated abstracts were read and categorised using predefined criteria. Results showed that arthropod vector-borne diseases in particular are recognised as having potential to expand their distribution towards Northern latitudes and that tick-borne encephalitis and borreliosis, midge-borne bluetongue and the parasitic infection fasciolosis can be classified as climate-sensitive. Many of the other potential CSIs considered are affected by extreme weather events, but could not be clearly classified as climate-sensitive. An additional literature search comparing awareness of climate influences on potential CSIs between 1997-2006 and 2007-2016 showed an increase in the number of papers mentioning effects of climate change.

CONCLUSIONS

The four CSIs identified in this study could be targeted in a systematic surveillance programme in Northern regions. It is evident that climate change can affect the epidemiology and geographical range of many infectious diseases, but there were difficulties in identifying additional CSIs, most likely because other factors may be of equal or greater importance. However, climate-ecological dynamics are constantly under change, and therefore diseases may fall in or out of the climate-sensitive definition over time. There is increasing awareness in the literature of the effects of climate change on infectious diseases over time.

The relation between Blastocystis and the intestinal microbiota in Swedish travellers

Background

Blastocystis sp. is a unicellular eukaryote that is commonly found in the human intestine. Its ability to cause disease is debated and a subject for ongoing research. In this study, faecal samples from 35 Swedish university students were examined through shotgun metagenomics before and after travel to the Indian peninsula or Central Africa. We aimed at assessing the impact of travel on Blastocystis carriage and seek associations between Blastocystis and the bacterial microbiota.

Results

We found a prevalence of Blastocystis of 16/35 (46%) before travel and 15/35 (43%) after travel. The two most commonly Blastocystis subtypes (STs) found were ST3 and ST4, accounting for 20 of the 31 samples positive for Blastocystis. No mixed subtype carriage was detected. All ten individuals with a typable ST before and after travel maintained their initial ST. The composition of the gut bacterial community was not significantly different between Blastocystis-carriers and non-carriers. Interestingly, the presence of Blastocystis was accompanied with higher abundances of the bacterial genera Sporolactobacillus and Candidatus Carsonella. Blastocystis carriage was positively associated with high bacterial genus richness, and negatively correlated to the Bacteroides-driven enterotype. These associations were both largely dependent on ST4 – a subtype commonly described from Europe – while the globally prevalent ST3 did not show such significant relationships.

Conclusions

The high rate of Blastocystis subtype persistence found during travel indicates that long-term carriage of Blastocystis is common. The associations between Blastocystis and the bacterial microbiota found in this study could imply a link between Blastocystis and a healthy microbiota as well as with diets high in vegetables. Whether the associations between Blastocystis and the microbiota are resulting from the presence of Blastocystis, or are a prerequisite for colonization with Blastocystis, are interesting questions for further studies.

Electronic supplementary material

The online version of this article (10.1186/s12866-017-1139-7) contains supplementary material, which is available to authorized users.

Biodiversity redistribution under climate change: Impacts on ecosystems and human well-being

Distributions of Earth's species are changing at accelerating rates, increasingly driven by human-mediated climate change. Such changes are already altering the composition of ecological communities, but beyond conservation of natural systems, how and why does this matter? We review evidence that climate-driven species redistribution at regional to global scales affects ecosystem functioning, human well-being, and the dynamics of climate change itself. Production of natural resources required for food security, patterns of disease transmission, and processes of carbon sequestration are all altered by changes in species distribution. Consideration of these effects of biodiversity redistribution is critical yet lacking in most mitigation and adaptation strategies, including the United Nation's Sustainable Development Goals.

Managing consequences of climate-driven species redistribution requires integration of ecology, conservation and social science

Climate change is driving a pervasive global redistribution of the planet's species. Species redistribution poses new questions for the study of ecosystems, conservation science and human societies that require a coordinated and integrated approach. Here we review recent progress, key gaps and strategic directions in this nascent research area, emphasising emerging themes in species redistribution biology, the importance of understanding underlying drivers and the need to anticipate novel outcomes of changes in species ranges. We highlight that species redistribution has manifest implications across multiple temporal and spatial scales and from genes to ecosystems. Understanding range shifts from ecological, physiological, genetic and biogeographical perspectives is essential for informing changing paradigms in conservation science and for designing conservation strategies that incorporate changing population connectivity and advance adaptation to climate change. Species redistributions present challenges for human well-being, environmental management and sustainable development. By synthesising recent approaches, theories and tools, our review establishes an interdisciplinary foundation for the development of future research on species redistribution. Specifically, we demonstrate how ecological, conservation and social research on species redistribution can best be achieved by working across disciplinary boundaries to develop and implement solutions to climate change challenges. Future studies should therefore integrate existing and complementary scientific frameworks while incorporating social science and human-centred approaches. Finally, we emphasise that the best science will not be useful unless more scientists engage with managers, policy makers and the public to develop responsible and socially acceptable options for the global challenges arising from species redistributions.

High occurrence of Blastocystis sp. subtypes 1-3 and Giardia intestinalis assemblage B among patients in Zanzibar, Tanzania

BACKGROUND

Blastocystis is a common intestinal parasite with worldwide distribution but the distribution of Blastocystis and its subtypes in East Africa is largely unknown. In this study, we investigate the distribution of Blastocystis subtypes in Zanzibar, Tanzania and report the prevalence of intestinal parasites using both molecular methods and microscopy.

METHODS

Stool samples were collected from both diarrhoeic and non-diarrhoeic outpatients in Zanzibar. In addition to microscopy, real-time PCR for Blastocystis, Entamoeba histolytica and E. dispar, Giardia intestinalis, Cryptosporidium spp., and Dientamoeba fragilis was used. Blastocystis subtypes were determined by a conventional PCR followed by partial sequencing of the SSU-rRNA gene. Genetic assemblages of Giardia were determined by PCR with assemblage specific primers.

RESULTS

Intestinal parasites were detected in 85 % of the 174 participants, with two or more parasites present in 56 %. Blastocystis sp. and Giardia intestinalis were the most common parasites, identified by PCR in 61 and 53 % of the stool samples respectively, but no correlation between carriage of Blastocystis and Giardia was found. The Blastocystis subtype distribution was ST1 34.0 %, ST2 26.4 %, ST3 25.5 %, ST7 0.9 %, and 13.2 % were positive only by qPCR (non-typable). The Giardia genetic assemblages identified were A 6.5 %, B 85 %, A + B 4.3 %, and non-typable 4.3 %. The detection rate with microscopy was substantially lower than with PCR, 20 % for Blastocystis and 13.8 % for Giardia. The prevalence of Blastocystis increased significantly with age while Giardia was most prevalent in children two to five years old. No correlation between diarrhoea and the identification of Giardia, Blastocystis, or their respective genetic subtypes could be shown and, as a possible indication of parasite load, the mean cycle threshold values in the qPCR for Giardia were equal in diarrhoeic and non-diarrhoeic patients.

CONCLUSIONS

Carriage of intestinal parasites was very common in the studied population in Zanzibar. The most commonly detected parasites, Blastocystis and Giardia, had different age distributions, possibly indicating differences in transmission routes, immunity, and/or other host factors for these two species. In the Blastocystis subtype analysis ST1-3 were common, but ST4, a subtype quite common in Europe, was completely absent, corroborating the geographical differences in subtype distributions previously reported.

Evaluation of factors affecting real-time PCR performance for diagnosis of Entamoeba histolytica and Entamoeba dispar in clinical stool samples

Although PCR offers the potential for sensitive detection of parasites there are several pitfalls for optimal performance, especially when DNA is extracted from a complex sample material such as stool. With the aid of a sensitive inhibitor control in a duplex real-time PCR (qPCR) for identification of Entamoeba histolytica and Entamoeba dispar we have evaluated factors that influenced the performance of the qPCR and have suggested a rationale to be used in the analysis of clinical samples. Pre-PCR processing was found to be of outmost importance for an optimal amplification since inhibitors caused false-negative results when higher amounts of sample were used. Stool sampling with a flocked swab (ESwab, Copan), yielding on average 173 mg, gave positive qPCR results in samples with cysts of E. dispar that were negative in serially diluted stool samples. The degree of inhibition found varied between samples and was not an on-off phenomenon. Even low-grade inhibition, shown as an increase of two cycles in the qPCR for the inhibitor control, could lead to false negativity in samples with low amounts of parasites. Lack of amplification in the qPCR due to inhibition could be overcome by dilution of the extracted DNA by 1/10-1/20. We also describe the use of guanidinium thiocyanate buffer for transport and storage of samples as well as a time-saving semi-automated DNA extraction method in an Arrow instrument (Nordiag) preceded by bead beating.

Illness and risk behaviour in health care students studying abroad

CONTEXT

The numbers of university students studying abroad increase every year. These students are not tourists as their studies require different types of travel that expose them to different risks. Moreover, health care students (HCSs) may be exposed to even greater risks according to their travel destinations and itineraries. Clearly, research-based pre-travel advice is needed.

METHODS

This study reports on a prospective survey conducted from April 2010 to January 2014 of health care and non-health care students from Swedish universities in Umeå, Stockholm and Gothenburg studying abroad.

RESULTS

Of the 393 students included in the study, 85% responded. Over half (55%) were HCSs. Pre-travel health information was received by 79% and information on personal safety by 49% of HCSs. The rate of illness during travel was 52%. Health care students more often travelled to developing regions and were at increased risk for travellers' diarrhoea. One in 10 experienced theft and 3% were involved in traffic accidents. One in five met a new sexual partner during travel and 65% of these practised safe sex. Half of all participants increased their alcohol consumption while abroad; high alcohol consumption was associated with increased risk for being a victim of theft, as well as for meeting a new sexual partner during travel.

CONCLUSIONS

University authorities are responsible for the safety and well-being of students studying abroad. This study supplies organisers and students with epidemiological data that will help improve pre-travel preparation and increase student awareness of the potential risks associated with studying abroad.

Risk factors for colonization with extended-spectrum beta-lactamase producing Enterobacteriaceae in healthcare students on clinical assignment abroad: A prospective study

BACKGROUND

The increase of antibiotic resistance in clinically important bacteria is a worldwide threat, especially in healthcare environments. International travel is a risk factor for gut colonization with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). The risk for healthcare students of being colonized with ESBL-PE when participating in patient-related work abroad has not been previously investigated.

METHODS

Swedish healthcare students travelling for pre-clinical and clinical courses outside Scandinavia submitted faecal samples and survey data before and after travel. The faecal samples were screened for ESBL-PE and carbapenemase-producing Enterobacteriaceae (CPE). Screening results and survey data were analysed to identify risk factors for colonization.

RESULTS

In the 99 subjects who submitted a full set of samples, 35% were colonized with a new ESBL-PE strain during travel. No CPE was found. The most important risk factor for ESBL-PE colonization was travel destination, and the highest colonization rate was found in the South-East Asia region. Antibiotic treatment during travel was an independent risk factor for ESBL-PE colonization but patient-related work was not significantly associated with an increased risk.

CONCLUSIONS

Patient-related work abroad was not a risk factor for ESBL-PE suggesting that transmission from patients is uncommon. Pre-travel advice on avoiding unnecessary antibiotic treatment during travel is recommended.

Low-educated women with chronic pain were less often selected to multidisciplinary rehabilitation programs

Background

There is a lack of research about a potential education-related bias in assessment of patients with chronic pain. The aim of this study was to analyze whether low-educated men and women with chronic pain were less often selected to multidisciplinary rehabilitation than those with high education.

Methods

The population consisted of consecutive patients (n = 595 women, 266 men) referred during a three-year period from mainly primary health care centers for a multidisciplinary team assessment at a pain rehabilitation clinic at a university hospital in Northern Sweden. Patient data were collected from the Swedish Quality Registry for Pain Rehabilitation National Pain Register. The outcome variable was being selected by the multidisciplinary team assessment to a multidisciplinary rehabilitation program. The independent variables were: sex, age, born outside Sweden, education, pain severity as well as the hospital, anxiety and depression scale (HADS).

Results

Low-educated women were less often selected to multidisciplinary rehabilitation programs than high-educated women (OR 0.55, CI 0.30–0.98), even after control for age, being born outside Sweden, pain intensity and HADS. No significant findings were found when comparing the results between high- and low-educated men.

Conclusion

Our findings can be interpreted as possible discrimination against low-educated women with chronic pain in hospital referrals to pain rehabilitation. There is a need for more gender-theoretical research emphasizing the importance of taking several power dimensions into account when analyzing possible bias in health care.

A call for urgent monitoring of food and water security based on relevant indicators for the Arctic

This perspective paper argues for an urgent need to monitor a set of 12 concrete, measurable indicators of food and water security in the Arctic over time. Such a quantitative indicator approach may be viewed as representing a reductionist rather than a holistic perspective, but is nevertheless necessary for actually knowing what reality aspects to monitor in order to accurately understand, quantify, and be able to project critical changes to food and water security of both indigenous and non-indigenous people in the Arctic. More relevant indicators may be developed in the future, taking us further toward reconciliation between reductionist and holistic approaches to change assessment and understanding. However, the potential of such further development to improved holistic change assessment is not an argument not to urgently start to monitor and quantify the changes in food and water security indicators that are immediately available and adequate for the Arctic context.

Food and water security issues in Russia I: food security in the general population of the Russian Arctic, Siberia and the Far East, 2000-2011

BACKGROUND

Problems related to food security in Russian Arctic (dietary imbalance, predominance of carbohydrates, shortage of milk products, vegetables and fruits, deficit of vitamins and microelements, chemical, infectious and parasitic food contamination) have been defined in the literature. But no standard protocol of food security assessment has been used in the majority of studies.

OBJECTIVES

Our aim was to obtain food security indicators, identified within an Arctic collaboration, for selected regions of the Russian Arctic, Siberia and the Far East, and to compare food safety in these territories.

STUDY DESIGN AND METHODS

In 18 regions of the Russian Arctic, Siberia and the Far East, the following indicators of food security were analyzed: food costs, food consumption, and chemical and biological food contamination for the period 2000-2011.

RESULTS

Food costs in the regions are high, comprising 23-43% of household income. Only 4 out of 10 food groups (fish products, cereals, sugar, plant oil) are consumed in sufficient amounts. The consumption of milk products, eggs, vegetables, potatoes, fruits (and berries) is severely low in a majority of the selected regions. There are high levels of biological contamination of food in many regions. The biological and chemical contamination situation is alarming, especially in Chukotka. Only 7 food pollutants are under regular control; among pesticides, only DDT. Evenki AO and Magadan Oblast have reached peak values in food contaminants compared with other regions. Mercury in local fish has not been analyzed in the majority of the regions. In 3 regions, no monitoring of DDT occurs. Aflatoxins have not been analyzed in 5 regions. Nitrates had the highest percentage in excess of the hygienic threshold in all regions. Excesses of other pollutants in different regions were episodic and as a rule not high.

CONCLUSION

Improvement of the food supply and food accessibility in the regions of the Russian Arctic, Siberia and the Far East is of utmost importance. Both quantitative and qualitative control of chemical and biological contaminants in food is insufficient and demands radical enhancement aimed at improving food security.

Indicators of food and water security in an Arctic Health context--results from an international workshop discussion

In August 2012, a literature search with the aim of describing indicators on food and water security in an Arctic health context was initialized in collaboration between the Arctic Human Health Expert Group, SDWG/AHHEG and the AMAP (Arctic Monitoring and Assessment Programme within the Arctic Council) Human Health Assessment Group, AMAP/HHAG. In December 2012, workshop discussions were performed with representatives from both of these organizations, including 7 Arctic countries. The aim of this article is to describe the workshop discussions and the rational for the 12 indicators selected and the 9 rejected and to discuss the potential feasibility of these. Advantages and disadvantages of candidate indicators were listed. Informative value and costs for collecting were estimated separately on a 3-level scale: low, medium and high. Based on these reviews, the final selection of promoted and rejected indicators was performed and summarized in tables. Among 10 suggested indicators of food security, 6 were promoted: healthy weight, traditional food proportion in diet, monetary food costs, non-monetary food accessibility, food-borne diseases and food-related contaminants. Four were rejected: per-person dietary energy supply, food security modules, self-estimated food safety and healthy eating. Among 10 suggested indicators of water security, 6 were promoted: per-capita renewable water, accessibility of running water, waterborne diseases, drinking-water-related contaminants, authorized water quality assurance and water safety plans. Four were rejected: water consumption, types of water sources, periodic water shortages and household water costs.

The influence of seasonal climate variability on mortality in pre-industrial Sweden

Background

Recent studies have shown an association between weather and climatic factors with mortality, cardiovascular and infectious diseases. We used historical data to investigate the impact of seasonal temperature and precipitation on total mortality in Uppsala, Sweden, during the first two stages of the demographic transition, 1749–1859.

Design

We retrieved mortality and population numbers of the Uppsala Domkyrka parish from digitised parish records and obtained monthly temperature and precipitation measures recorded in Uppsala during that time. Statistical models were established for year-to-year variability in deaths by annual and seasonal temperature and precipitation, adjusting for longer time trends. In a second step, a model was established for three different periods to study changes in the association of climate variability and mortality over time. Relative risks (RR) with 95% confidence intervals (CI) were calculated.

Results

Precipitation during spring and autumn was significantly associated with annual mortality (spring RR 0.982, CI 0.965–1.000; autumn RR 1.018, CI 1.004–1.032, respectively, per centimetre increase of precipitation). Higher springtime temperature decreased annual mortality, while higher summer temperature increased the death toll; however, both were only borderline significant (p=0.07). The significant effect of springtime precipitation for mortality was present only in the first two periods (1749–1785 and 1786–1824). On the contrary, the overall effect of autumn precipitation was mainly due to its relevance during the last period, 1825–1859 (RR 1.024, CI 0.997–1.052). At that time, higher winter precipitation was found to decrease mortality.

Conclusions

In urban Uppsala, during the 18th and 19th century, precipitation appeared to be a stronger predictor for mortality than temperature. Higher spring precipitation decreased and higher autumn precipitation increased the number of deaths. However, this association differed before and during the early stages of industrialisation. Further research shall take age-specific differences into account, as well as changes in socio-economic conditions during that time.

Connecting the global climate change and public health agendas

Peter Byass and colleagues urge public health professionals to strengthen their response and develop actions to bring health and climate co-benefits.

Facing the limit of resilience: perceptions of climate change among reindeer herding Sami in Sweden

Background

The Arctic area is a part of the globe where the increase in global temperature has had the earliest noticeable effect and indigenous peoples, including the Swedish reindeer herding Sami, are amongst the first to be affected by these changes.

Objective

To explore the experiences and perceptions of climate change among Swedish reindeer herding Sami.

Study design

In-depth interviews with 14 Swedish reindeer herding Sami were performed, with purposive sampling. The interviews focused on the herders experiences of climate change, observed consequences and thoughts about this. The interviews were analysed using content analysis.

Results

One core theme emerged from the interviews: facing the limit of resilience. Swedish reindeer-herding Sami perceive climate change as yet another stressor in their daily struggle. They have experienced severe and more rapidly shifting, unstable weather with associated changes in vegetation and alterations in the freeze–thaw cycle, all of which affect reindeer herding. The forecasts about climate change from authorities and scientists have contributed to stress and anxiety. Other societal developments have lead to decreased flexibility that obstructs adaptation. Some adaptive strategies are discordant with the traditional life of reindeer herding, and there is a fear among the Sami of being the last generation practising traditional reindeer herding.

Conclusions

The study illustrates the vulnerable situation of the reindeer herders and that climate change impact may have serious consequences for the trade and their overall way of life. Decision makers on all levels, both in Sweden and internationally, need improved insights into these complex issues to be able to make adequate decisions about adaptive climate change strategies.

An unbiased metagenomic search for infectious agents using monozygotic twins discordant for chronic fatigue

BACKGROUND

Chronic fatigue syndrome is an idiopathic syndrome widely suspected of having an infectious or immune etiology. We applied an unbiased metagenomic approach to try to identify known or novel infectious agents in the serum of 45 cases with chronic fatigue syndrome or idiopathic chronic fatigue. Controls were the unaffected monozygotic co-twins of cases, and serum samples were obtained at the same place and time.

RESULTS

No novel DNA or RNA viral signatures were confidently identified. Four affected twins and no unaffected twins evidenced viremia with GB virus C (8.9% vs. 0%, p = 0.019), and one affected twin had previously undetected hepatitis C viremia. An excess of GB virus C viremia in cases with chronic fatigue requires confirmation.

CONCLUSIONS

Current, impairing chronic fatigue was not robustly associated with viremia detectable in serum.

The gender perspective in climate change and global health

BACKGROUND

Population health is a primary goal of sustainable development. United Nations international conferences like the Beijing Platform for Action have highlighted the key role of women in ensuring sustainable development. In the context of climate change, women are affected the most while they display knowledge and skills to orient themselves toward climate adaptation activities within their societies.

OBJECTIVE

To investigate how the gender perspective is addressed as an issue in research and policy-making concerning climate change and global health.

METHODS

A broad literature search was undertaken using the databases Pubmed and Web of Science to explore the terms 'climate change,' 'health,' 'gender,' and 'policy.' Climate change and health-related policy documents of the World Health Organization (WHO) and National Communications and National Adaptation Programs of Action reports submitted to the United Nations Framework Convention on Climate Change of selected countries were studied. Assessment guidelines to review these reports were developed from this study's viewpoint.

RESULTS

The database search results showed almost no articles when the four terms were searched together. The WHO documents lacked a gender perspective in their approach and future recommendations on climate policies. The reviewed UN reports were also neutral to gender perspective except one of the studied documents.

CONCLUSION

Despite recognizing the differential effects of climate change on health of women and men as a consequence of complex social contexts and adaptive capacities, the study finds gender to be an underrepresented or non-existing variable both in research and studied policy documents in the field of climate change and health.

Evaluation of rapid diagnostic tests for malaria in Swedish travellers

Rapid diagnostic tests (RDTs) for malaria have become valuable tools for the diagnosis of malaria in both endemic and non-endemic areas. During a 7-year period, first the MalaQuick rapid test and then the NOW Malaria test, were evaluated by well-trained laboratory technicians in a university hospital laboratory of parasitology. A total of 635 blood samples were selected from 4731 blood specimens obtained from travellers at the emergency department, at wards and at out-patient clinics. The samples were analysed by microscopy and RDT. Malaria parasites were detected in the blood films of 134 (21%) samples. The sensitivity of the RDT for Plasmodium falciparum was 97.7% (84 of 86 samples) with a negative predictive value of 99.6%. The two false-negative results were associated with low levels of parasitaemia. For non-falciparum species the sensitivity was only 58.3% (28 of 48 samples). Based on the excellent ability of the RDTs to detect P. falciparum infections, we recommend the use of the NOW Malaria test as a complement to microscopy in the laboratory.

Toxoplasmosis not transmitted by cat bite, but high prevalence of antibodies to Toxoplasma gondii in patients bitten by their own cat

The aims of the study were to investigate the prevalence of antibodies to Toxoplasma gondii in a group of patients bitten by cats, and also to determine if toxoplasmosis can be transferred by cat bite. Seventy-two patients who attended the emergency wards at 3 hospitals in Stockholm, Sweden, due to infection by cat bite, were investigated for specific IgM and IgG antibodies to T. gondii in the acute phase, as well as in the convalescent phase about 2 weeks later. Specific IgG antibodies to T. gondii (> or =8 IU/ml) were found in 17/72 patients (24%) in the acute phase. No case of seroconversion occurred. Patients who were bitten by their own cat had positive antibody titres to T. gondii significantly more often than those bitten by a foreign cat; 30% and 5%, respectively (p = 0.02). This suggests that regular contact with cats may contribute to the transmission of the parasite.

Toxoplasmosis in immunocompromized patients

Infection with the cosmopolitan parasite Toxoplasma gondii is often associated with severe consequences and a high mortality rate in immunocompromized patients. Non-specific symptoms make diagnosis challenging. Monitoring of patients at risk is of value. We here present 8 cases of toxoplasmosis in immunocompromized patients with suggestions for preventive monitoring.

A population-based twin study of functional somatic syndromes

BACKGROUND

The mechanisms underlying the co-occurrence of the functional somatic syndromes are largely unknown. No empirical study has explicitly examined how genetic and environmental factors influence the co-morbidity of these syndromes. We aimed to examine how the co-morbidity of functional somatic syndromes is influenced by genetic and environmental factors that are in common to the syndromes.

METHOD

A total of 31318 twins in the Swedish Twin Registry aged 41-64 years underwent screening interviews via a computer-assisted telephone system from 1998 to 2002. Four functional somatic syndromes (chronic widespread pain, chronic fatigue, irritable bowel syndrome, and recurrent headache) and two psychiatric disorders (major depression and generalized anxiety disorder) were assessed using structured questions based on standard criteria for each illness in a blinded manner.

RESULTS

Multivariate twin analyses revealed that a common pathway model with two latent traits that were shared by the six illnesses fit best to the women's data. One of the two latent traits loaded heavily on the psychiatric disorders, whereas the other trait loaded on all four of the functional somatic syndromes, particularly chronic widespread pain, but not on the psychiatric disorders. All illnesses except the psychiatric disorders were also affected by genetic influences that were specific to each.

CONCLUSIONS

The co-occurrence of functional somatic syndromes in women can be best explained by affective and sensory components in common to all these syndromes, as well as by unique influences specific to each of them. The findings clearly suggest a complex view of the multifactorial pathogenesis of these illnesses.

Effect of supplement with lactic-acid producing bacteria on fatigue and physical activity in patients with chronic fatigue syndrome

Disturbances in intestinal microbial ecology and in the immune system of the host have been implicated as a part of the pathogenesis in chronic fatigue syndrome. Probiotic lactic acid producing bacteria have been shown to prevent and alleviate gastrointestinal disturbances and to normalize the cytokine profile which might be of an advantage for patients suffering from chronic fatigue syndrome. The aim of the study was to evaluate the effect of Lactobacillus paracasei ssp. paracasei F19, Lactobacillus acidophilus NCFB 1748 and Bifidobacterium lactis Bb12 on fatigue and physical activity in CFS patients. Fifteen patients fulfilling the criteria set by international researchers in the field at the US Centre for Disease Control and Prevention in 1994 for chronic fatigue syndrome, were included in the study. The patients had high fatigue severity scores and high disability scores. During the first two weeks baseline observations without treatment were assessed, succeeded by four weeks of intake of a probiotic product and a four-week follow-up period. The fatigue, health and physical activity was assessed by the use of the Visual Analogue Scales and the SF-12 Health Survey. Faecal samples were collected and the normal microflora was analysed. Neurocognitive functions improved during the study period while there were no significant changes in fatigue and physical activity scores. No major changes occurred in the gastrointestinal microflora. At the end of the study 6 of 15 patients reported that they had improved according to the assessment described. The findings in this study that improvement of health is possible to achieve should encourage further studies with interventions with probiotics in patients with CFS.

A prospective study of diagnosis of Toxoplasma gondii infection after bone marrow transplantation

Active infection with Toxoplasma gondii in immunocompromised transplant recipients can lead to toxoplasmosis, which may have a rapid disease course and in some cases be fatal. It is of paramount importance to diagnose toxoplasmosis at an early stage, and to initiate specific treatment to improve the outcome. Polymerase chain reaction (PCR) is today the primary diagnostic tool to diagnose toxoplasmosis in immunocompromised patients. Timely diagnosis may, however, be difficult if toxoplasmosis is at first asymptomatic. To investigate the magnitude of toxoplasmosis after bone marrow transplantation (BMT), we conducted a screening study by PCR where 21 autologous and 12 allogeneic BMT recipients were included. Peripheral blood samples were taken one week prior to BMT; thereafter, blood samples were drawn weekly for the first 6 months, and monthly up to one year after BMT. The samples were analyzed by conventional PCR and real-time PCR. T. gondii DNA was detected in peripheral blood from one patient 5 days post allogeneic BMT. There were no clinical signs of toxoplasmosis. Medical records were reviewed and showed a previously undiagnosed eye infection in another allogeneic BMT recipient. These two patients were seropositive for T. gondii. We concluded that monitoring for T. gondii DNA in peripheral blood samples using PCR might be a valuable method for identifying toxoplasma-seropositive stem cell transplant recipients.

"The Laundry Bag Project"--unequal distribution of dermatological healthcare resources for male and female psoriatic patients in Sweden

BACKGROUND

Psoriasis and eczema are common dermatological diseases that occur with approximately equal frequency in men and in women. The aim of this study was to determine whether men and women with dermatological diseases in need of ultra-violet radiation (UV) treatment receive equal care.

METHODS

We conducted a retrospective analysis of records of all patients referred to and seen at our clinic during 2003 with diagnoses of psoriasis or eczema. We performed a gender-based analysis of the number, type, and estimated cost of the treatments given to each patient. We evaluated similar data from a Swedish Psoriasis Association (SPA) treatment center and from the state pharmacy monopoly (Apoteksstatistiken).

RESULTS

Men with eczema or psoriasis received more help with emollients than did women and were given a greater number of UV treatments. At our clinic and at the SPA center, women constituted 37 and 42%, respectively, of the individuals who received UV treatment; yet, they received only 34 and 36% of the treatments, respectively. Women were prescribed self-care more often than men, with 61% of prescriptions for emollients and 48% of specific topical treatments for psoriasis dispensed to women.

CONCLUSIONS

We discovered previously unrecognized gender differences in standard dermatological treatment for common diagnoses at our hospital. To ensure optimal care for each patient, treatment disparity should be recognized and gender-based analyzes be carried out when planning dermatological health care.

Rapid genotyping of Toxoplasma gondii by pyrosequencing

Most human infections with the protozoan parasite Toxoplasma gondii are asymptomatic, but severe symptoms can occur in immunocompromised patients, in developing foetuses, and in ocular infections in immunocompetent individuals. The majority of T. gondii strains can be divided into three main lineages, denoted types I, II and III, which are known to cause different clinical presentations. Simple molecular methods with the capacity to discriminate rapidly among strains may help to predict the course of infection and influence the choice of treatment. In the present study, real-time PCR followed by pyrosequencing was used to discriminate among types I, II and III by analysis of two single nucleotide polymorphisms in the GRA6 gene. Twenty-one isolates of T. gondii characterised previously were analysed. Three different GRA6 alleles detected by the pyrosequencing technique identified types I, II and III isolates correctly, while four atypical isolates possessed either the GRA6 allele 1 or the GRA6 allele 3. Reproducibility was 100%, and typeability, when including atypical strains, was 81%. It was also possible to discriminate a mixture of two genotypes. The method was used to identify GRA6 type II in blood and lung tissue from an allogeneic transplant recipient with toxoplasmosis.

β-Alanine and γ-aminobutyric acid in chronic fatigue syndrome

BACKGROUND

Due to the occurrence of sleep disturbances and fatigue in chronic fatigue syndrome (CFS), an investigation was performed to examine if there is an abnormal excretion of gamma-aminobutyric acid (GABA) and/or its structural analogue beta-alanine in the urine from CFS patients. Both GABA and beta-alanine are inhibitory neurotransmitters in the mammalian central nervous system.

METHODS

The 24 h urine excretion of GABA and beta-alanine was determined by isotope dilution gas chromatography mass spectrometry in 33 CFS patients and 43 healthy controls. The degree of symptoms in both patients and controls was measured by grading of three typical CFS symptoms using a Visual Analogue Scale.

RESULTS

Men had a significantly higher excretion of both beta-alanine and GABA than women. Comparing CFS patients with healthy controls showed no significant difference in excretion of neither beta-alanine nor GABA. No correlation was found between the excretion of beta-alanine or GABA and any of the three characteristic CFS symptoms measured. However, two female and two male CFS patients excreted considerably higher amounts of beta-alanine in their 24 h urine samples than control subjects.

CONCLUSIONS

Increased excretion of beta-alanine was found in a subgroup of CFS patients, indicating that there may be a link between CFS and beta-alanine in some CFS patients.

Premorbid predictors of chronic fatigue

CONTEXT

Chronic fatigue syndrome is a disabling problem characterized by persistent fatigue lasting at least 6 months with a number of ancillary symptoms. Although the etiology of chronic fatiguing illness is unknown, some evidence suggests that stress may confer increased risk for development of the disorder. Moreover, subjects with chronic fatiguing illness may have distinctive personality traits, although this finding could reflect confounding by other mechanisms.

OBJECTIVE

To assess the prospective association of premorbid self-reported stress and personality with chronic fatigue-like illness.

DESIGN

Prospective nested case-control study in a population-based sample.

SETTING

General community.

PARTICIPANTS

From the Swedish Twin Registry, 19,192 twins born between January 1, 1935, and December 31, 1958.

MAIN OUTCOME MEASURES

Information about current chronic fatiguing illnesses was obtained from computer-assisted telephone interviews conducted between 1998 and 2002. Self-reported stress (based on a single question) and personality scales (emotional instability and extraversion in the Eysenck Personality Inventory) were measured from 1972 to 1973 by a mailed questionnaire. Relative risks were estimated with case-control analyses (matched for age and sex) and co-twin control analyses (comparing discordant pairs).

RESULTS

Higher emotional instability and self-reported stress in the premorbid period were associated with higher risk for chronic fatigue-like illness in matched case-control analyses (odds ratios, 1.72 and 1.64, respectively). In co-twin control analyses, relative risk of emotional instability decreased to 1.02 whereas that of stress increased considerably to 5.81. There was no association between extraversion and fatigue.

CONCLUSIONS

Elevated premorbid stress is a significant risk factor for chronic fatigue-like illness, the effect of which may be buffered by genetic influences. Emotional instability assessed 25 years earlier is associated with chronic fatigue through genetic mechanisms contributing to both personality style and expression of the disorder. These findings suggest plausible mechanisms for chronic fatiguing illness.

Chronic widespread pain and its comorbidities: a population-based study

BACKGROUND

Chronic widespread pain (CWP), the cardinal symptom of fibromyalgia, is prevalent and co-occurs with numerous symptom-based conditions such as chronic fatigue syndrome, joint pain, headache, irritable bowel syndrome, and psychiatric disorders. Few studies have examined the comorbidities of CWP in the general population. Furthermore, little is known about the importance of familial (genetic and family environmental) factors in the etiology of co-occurrence.

METHODS

Data were obtained from 44 897 individuals in the Swedish Twin Registry via computer-assisted telephone interview from 1998 through 2002 (age >/=42 years; 73.2% response rate). Screening for CWP was based on the American College of Rheumatology criteria without clinical evaluation. Measures for comorbidities were based on standard criteria when available. Odds ratios (ORs) were calculated in case-control and co-twin control designs to assess the effect of familial confounding in the associations.

RESULTS

Considerable co-occurrences were found in CWP cases for chronic fatigue (OR, 23.53; 95% confidence interval [CI], 19.67-28.16), joint pain (OR, 7.41; 95% CI, 6.70-8.21), depressive symptoms (OR, 5.26; 95% CI, 4.75-5.82), and irritable bowel syndrome (OR, 5.17; 95% CI, 4.55-5.88). In co-twin control analyses, ORs were no longer significant for psychiatric disorders, whereas they decreased but remained significant for most other comorbidities. No changes in ORs were observed for headache.

CONCLUSIONS

Associations between CWP and most comorbidities are mediated by unmeasured genetic and family environmental factors in the general population. The extent of mediation via familial factors is likely to be disorder specific.

Real-time PCR targeting a 529-bp repeat element for diagnosis of toxoplasmosis

Sensitive and rapid detection of infection with Toxoplasma gondii in transplanted immunocompromised patients is crucial for a good prognosis. Two DNA fragments are used currently for detecting T. gondii infection by PCR, i.e., the B1 gene and a 529-bp repeat element that exists in 200-300 copies/genome. This study investigated whether targeting the 529-bp repeat element gives better sensitivity and accuracy than can be obtained when targeting the B1 gene (35 copies) when concentrations of T. gondii DNA are low. The results demonstrated that detection of the 529-bp repeat element increased diagnostic sensitivity and accuracy. Addition of an internal amplification control did not affect the PCR performance and was useful in order to monitor PCR inhibition by non-specific DNA in the LightCycler instrument. The real-time PCR was used successfully in a clinical context to monitor parasitaemia in the blood of a transplant recipient suffering from toxoplasmosis.

Diagnosis of pulmonary infection with Toxoplasma gondii in immunocompromised HIV-positive patients by real-time PCR

The aim of the study presented here was to evaluate the use of PCR for improving the diagnosis of Toxoplasma gondii infection in immunocompromised hosts. Three hundred thirty-two bronchoalveolar lavage (BAL) fluid samples were analyzed by real-time PCR targeting a 529 bp element of T. gondii. In positive samples, the genotype of the parasite was determined by sequence analysis of the GRA6 gene. Positive results were achieved for 2% (7/332) of the samples tested. Genotyping was possible in two samples and revealed GRA6 type II T. gondii. PCR for detecting T. gondii in BAL samples should be performed in all immunosuppressed HIV-positive patients with symptoms of a systemic infection of unknown etiology. Trimethoprim-sulfamethoxazole prophylaxis does not exclude concomitant infection with T. gondii.

Reduced levels of oestrogen receptor beta mRNA in Swedish patients with chronic fatigue syndrome

BACKGROUND

Chronic fatigue syndrome (CFS) is an illness with unknown aetiology and pathophysiology. The difference in incidence by sex observed for CFS indicates a role for oestrogen and oestrogen receptors in disease development. Furthermore, an immunomediated pathogenesis has been suggested for CFS, providing an additional connection to oestrogen, which displays immunomodular functions.

AIMS

To investigate a possible association of oestrogen receptor (ER) mRNAs and two ERbeta single-nucleotide polymorphisms (SNPs) with CFS.

METHODS

Messenger RNA levels of ERalpha, ERbeta wt and ERbeta cx were investigated in peripheral blood mononuclear cells from 30 patients with CFS and 36 healthy controls by quantitative real-time polymerase chain reaction. Two ERbeta SNPs were scored in the same material.

RESULTS

The CFS group showed significantly lower mRNA expression levels of ERbeta wt compared with the healthy control group. No differences were observed for ERalpha or ERbeta cx between patients and controls. There were no significant differences in frequency for the investigated ERbeta SNPs between cases and controls.

CONCLUSIONS

The reduced ERbeta wt expression level observed in this study is consistent with an immune-mediated pathogenesis of CFS. Additionally, the observation that ERbeta wt expression is decreased in CFS could provide an entry point to identify interesting, potentially disease-causing, candidate molecules for further study. A possible connection between oestrogen, oestrogen receptors and CFS should be evaluated further.

Importance of genetic influences on chronic widespread pain

OBJECTIVE

To estimate the relative importance of genetic and environmental factors in chronic widespread pain, and to assess whether there are sex differences in the type or magnitude of these influences.

METHODS

Data were collected from a national sample of twins > or = 42 years of age, all of whom were participants in the Swedish Twin Registry. The presence of chronic widespread pain was assessed via computer-assisted telephone interviews, which were conducted between 1998 and 2002, using the American College of Rheumatology criteria for fibromyalgia. No clinical examinations were performed. In preliminary analyses, probandwise concordance rates and tetrachoric correlations were calculated. Structural equation modeling was then performed to estimate additive genetic, shared environmental, and nonshared environmental sources of variability in susceptibility for the development of chronic widespread pain.

RESULTS

Of 61,355 eligible twins, 44,897 individuals (73.2%) responded to the interview. Both members of 15,950 pairs responded to the items regarding pain symptoms; of these pairs, 4,170 were monozygotic, 5,881 were same-sex dizygotic, and 5,755 were opposite-sex dizygotic. The prevalence of chronic widespread pain was 4.1%, and the ratio of women to men was 3.3 to 1. Probandwise concordance rates and tetrachoric correlations suggested modest genetic influences for both women and men. Genetic and shared environmental influences explained approximately half of the total variance, with no indication of sex differences in either the type or magnitude of these influences.

CONCLUSION

Individual differences in the likelihood of developing chronic widespread pain reflect modest genetic influences. There are no significant sex differences in the type or expression of the genes responsible for chronic widespread pain or in the magnitude of the relative importance of these influences on chronic widespread pain.

[The laundry-basket project--gender differences to the very skin. Different treatment of some common skin diseases in men and women]

In this study, we have analysed the treatment traditions in a dermatological outpatient clinic, from a gender perspective. Eczema and psoriasis were of similar frequency in male and female patients, while a higher number of female patients had eczema of the hands. Ultraviolet light (UV) treatment was given to a higher number of male patients in all diagnostic groups including eczema of the hands. In addition, a higher number of given treatments was given to the male patients than to the female patients. As for prescriptions to male and female patients from our department and in Stockholm county (1.8 mill.), a much larger amount of preparations for local treatment was received by female patients, especially emollients. Male patients had received more of calcipotriol creme in addition to their being treated more intensively at the clinic. In a sub-group analysis on patients with psoriasis vulgaris on our clinic and in a patient cooperation-based treatment department, we found the same relation between male and female treatment as in the larger group. On follow-up, the number of female patients with psoriasis who were given treatment at our clinic had increased, but the number of treatments given to men was still higher than for female patients. An economic analysis of these findings show a great overweight of clinic-based treatment costs for male patients, while female patients receive emollients for self-care to a greater extent. We conclude that more studies are needed to clarify the basis of these findings.

The epidemiology of chronic fatigue in the Swedish Twin Registry

BACKGROUND

Chronic fatigue syndrome (CFS) remains an idiopathic and controversial entity.

METHOD

We screened 31405 individual members of the Swedish Twin Registry (aged 42-64 years) for the symptoms of fatiguing illness via a telephone questionnaire. We refined self-reported symptoms via data from several national registries and from physician review of all available medical records in order to approximate closely the dominant case definition of CFS.

FINDINGS

The 6-month prevalence of CFS-like illness was 2.36% (95% CI 2.19-2.53) and was markedly higher in women than men, odds ratio 3.92 (95% CI 3.24-4.72) with no significant association with age or years of education. There was a highly significant association with occupation that disappeared after accounting for gender.

INTERPRETATION

CFS-like illness may be more common that previously acknowledged. There is a marked increase in risk by gender. Previous reports that CFS is more prevalent in individuals in certain occupational categories were not confirmed and may have been due to confounding by gender.

Chronic fatigue in a population sample: definitions and heterogeneity

BACKGROUND

Numerous nosological decisions are made when moving from the common human symptom of unusual fatigue to the rare chronic fatigue syndrome (CFS). These decisions have infrequently been subjected to rigorous evaluation.

METHOD

We obtained telephone interview data on fatiguing symptoms from 31406 individuals twins in the Swedish Twin Registry aged 42-64 years; 5330 subjects who endorsed fatigue and possessed no exclusionary condition formed the analytic group. We evaluated the definition and classification of CFS-like illness using graphical methods, regression models, and latent class analysis.

RESULTS

Our results raise fundamental questions about the 1994 Centers for Disease Control criteria as (1) there was no empirical support for the requirement of four of eight cardinal CFS symptoms; (2) these eight symptoms were not equivalent in their capacity to predict fatigue; and (3) no combination of symptoms was markedly more heritable. Critically, latent class analysis identified a syndrome strongly resembling CFS-like illness.

CONCLUSIONS

Our data are consistent with the 'existence' of CFS-like illness although the dominant nosological approach captures population-level variation poorly. We suggest that studying a more parsimonious case definition - impairing chronic fatigue not due to a known cause - would represent a way forward.

Twin analyses of chronic fatigue in a Swedish national sample

BACKGROUND

Chronic fatigue has infrequently been studied in twins. Data from twin studies can inform clinical and research approaches to the management and etiology of human complex traits.

METHOD

The authors obtained telephone interview data on current chronic fatigue from 31406 individuals twins in the Swedish Twin Registry (aged 42-64 years, 75.68% response rate), from both members of 12407 pairs and from one member of 6592 pairs. Of the complete pairs, 3269 pairs were monozygotic, 9010 pairs dizygotic, and 128 pairs of unknown zygosity. Structural equation twin modeling was used to estimate the latent genetic architecture of varying definitions of fatiguing illness.

RESULTS

Estimates of additive genetic effects, shared environmental effects, and individual-specific environmental effects were similar in males and females. No definition of current fatiguing illness (ranging from any fatigue to CFS-like illness) was strikingly distinctive. Individual-specific effects were the predominant source of variation, followed by modest genetic influences. We could not exclude a small but conceptually important contribution of shared environmental effects.

CONCLUSIONS

Current fatiguing illness appears to be a complex trait resulting from both environmental and genetic sources of variation without pronounced differences by gender.

DNA extraction and PCR assays for detection of Toxoplasma gondii

For detection of Toxoplasma gondii we compared the sensitivity of two different DNA extraction methods and three different PCR assays. Sensitivities of DNA extraction by QIAamp DNA mini Kit or MagNa pure followed by PCR, nested PCR and oligochromatography or Light Cycler PCR using either SYBR green chemistry or TaqMan probe were compared. No significant difference between extraction methods was found using pure T. gondii tachyzoites. Spiked blood samples, 10(4) to 10 parasites per sample, generated no difference in sensitivity between the two DNA extraction methods when analysed by nested PCR detected by oligochromatography or analysed by Light Cycler PCR TaqMan. In spiked blood samples Light Cycler PCR SYBR green was unable to detect the parasite and a reduction in sensitivity was observed with the TaqMan assay. Conventional PCR was more sensitive when DNA was extracted from the spiked samples using the QIAamp DNA mini Kit. Conventional and nested PCR were found to be more sensitive than Light Cycler PCR TaqMan using the QIAamp DNA mini Kit. It was not possible to use Light Cycler PCR SYBR green in blood samples. Conventional PCR was more sensitive for detection of T. gondii in spiked blood samples using QIAamp DNA mini Kit DNA extraction, suggesting that the choice of DNA extraction method may affect PCR assays differently.

Rapid and sensitive diagnosis of Toxoplasma gondii infections by PCR

DNA was extracted with a modified Qiagen DNA Mini Kit method from 20 clinical samples and was amplified by PCR using specific primers for the T. gondii B1 gene. T. gondii was detected correctly in 18 of the 20 clinical samples in < 5 h, with a detection limit of two parasites/sample. The results were in good agreement with those obtained by a more complicated and time-consuming procedure involving two-step nested PCR and either liquid hybridisation or colorimetric detection using internal probes.