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Parasites & Vectors Nov 2019Scrub typhus, caused by Orientia tsutsugamushi, is an important and neglected vector-borne zoonotic disease with an expanding known distribution. The ecology of the...
Scrub typhus, caused by Orientia tsutsugamushi, is an important and neglected vector-borne zoonotic disease with an expanding known distribution. The ecology of the disease is complex and poorly understood, impairing discussion of public health interventions. To highlight what we know and the themes of our ignorance, we conducted a systematic review of all studies investigating the pathogen in vectors and non-human hosts. A total of 276 articles in 7 languages were included, with 793 study sites across 30 countries. There was no time restriction for article inclusion, with the oldest published in 1924. Seventy-six potential vector species and 234 vertebrate host species were tested, accounting for over one million trombiculid mites ('chiggers') and 83,000 vertebrates. The proportion of O. tsutsugamushi positivity was recorded for different categories of laboratory test and host species. Vector and host collection sites were geocoded and mapped. Ecological data associated with these sites were summarised. A further 145 articles encompassing general themes of scrub typhus ecology were reviewed. These topics range from the life-cycle to transmission, habitats, seasonality and human risks. Important gaps in our understanding are highlighted together with possible tools to begin to unravel these. Many of the data reported are highly variable and inconsistent and minimum data reporting standards are proposed. With more recent reports of human Orientia sp. infection in the Middle East and South America and enormous advances in research technology over recent decades, this comprehensive review provides a detailed summary of work investigating this pathogen in vectors and non-human hosts and updates current understanding of the complex ecology of scrub typhus. A better understanding of scrub typhus ecology has important relevance to ongoing research into improving diagnostics, developing vaccines and identifying useful public health interventions to reduce the burden of the disease.
Topics: Animals; Arachnid Vectors; Geographic Mapping; Humans; Orientia tsutsugamushi; Scrub Typhus; Trombiculidae; Vertebrates; Zoonoses
PubMed: 31685019
DOI: 10.1186/s13071-019-3751-x -
BMC Infectious Diseases Dec 2023Scrub typhus is a bacterial mite-borne disease associated with poor clinical outcomes if not treated adequately. The study aimed to compare the time to defervescence,... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Scrub typhus is a bacterial mite-borne disease associated with poor clinical outcomes if not treated adequately. The study aimed to compare the time to defervescence, clinical failure, mortality and treatment-related adverse effects of two common drugs (doxycycline and azithromycin) used for its treatment.
METHODOLOGY
This was a systematic review and meta-analysis. All studies up to 20.03.2023 were screened for eligibility in Pubmed and Embase using a search string containing terms related to scrub typhus, doxycycline and azithromycin. After two phases of screening, all comparative studies where doxycycline and azithromycin were used to treat scrub typhus were included. The studies were critically appraised using standardised tools, and a meta-analysis was performed for time to defervescence (primary outcome), clinical failure, mortality and treatment-related adverse effects.
RESULTS
Of 744 articles from two databases, ten were included in the meta-analysis. All but two studies had a high risk of bias. The meta-analysis for time to defervescence had a high heterogeneity and did not show any significant difference between doxycycline and azithromycin arms [Mean difference of -3.37 hours (95%CI: -10.31 to 3.57), p=0.34]. When the analysis was restricted to studies that included only severe scrub typhus, doxycycline was found to have a shorter time to defervescence [mean difference of -10.15 (95%CI: -19.83 to -0.46) hours, p=0.04]. Additionally, there was no difference between the two arms concerning clinical failure, mortality and treatment-related adverse effects.
CONCLUSION
The current data from studies with a high risk of bias did not find statistically significant differences in clinical outcomes between doxycycline and azithromycin for scrub typhus.
Topics: Humans; Azithromycin; Doxycycline; Anti-Bacterial Agents; Scrub Typhus; Patients; Drug-Related Side Effects and Adverse Reactions
PubMed: 38110855
DOI: 10.1186/s12879-023-08893-7 -
Hereditas 2017Wheat is globally one of the most important crops. With the current human population growth rate, there is an increasing need to raise wheat productivity by means of... (Review)
Review
Wheat is globally one of the most important crops. With the current human population growth rate, there is an increasing need to raise wheat productivity by means of plant breeding, along with development of more efficient and sustainable agricultural systems. Damage by pathogens and pests, in combination with adverse climate effects, need to be counteracted by incorporating new germplasm that makes wheat more resistant/tolerant to such stress factors. Rye has been used as a source for improved resistance to pathogens and pests in wheat during more than 50 years. With new devastating stem and yellow rust pathotypes invading wheat at large acreage globally, along with new biotypes of pest insects, there is renewed interest in using rye as a source of resistance. Currently the proportion of wheat cultivars with rye chromatin varies between countries, with examples of up to 34%. There is mainly one rye source, Petkus, that has been widely exploited and that has contributed considerably to raise yields and increase disease resistance in wheat. Successively, the multiple disease resistances conferred by this source has been overcome by new pathotypes of leaf rust, yellow rust, stem rust and powdery mildew. However, there are several other rye sources reported to make wheat more resistant to various biotic constraints when their rye chromatin has been transferred to wheat. There is also development of knowledge on how to produce new rye translocation, substitution and addition lines. Here we compile information that may facilitate decision making for wheat breeders aiming to transfer resistance to biotic constraints from rye to elite wheat germplasm.
Topics: Crosses, Genetic; Disease Resistance; Plant Breeding; Secale; Translocation, Genetic; Triticum
PubMed: 28559761
DOI: 10.1186/s41065-017-0033-5 -
Journal of Vector Borne Diseases Jan 2024Rickettsial infections are emerging and/or re-emerging disease that poses a serious global threat to humans and animals. Transmission to humans and animals is through...
Rickettsial infections are emerging and/or re-emerging disease that poses a serious global threat to humans and animals. Transmission to humans and animals is through the bite of the ectoparasites including ticks, fleas and chigger mites. Most of the rickettsial diseases are endemic in India, but underdiagnosed. This review is aimed at analyzing the prevalence of rickettsiosis in India and the advancement of rickettsial diagnosis. We have conducted a systematic review on the prevalence of rickettsial disease in India ranging from 1.3% to 46.6% for spotted fever, 2.4% to 77.8% for scrub typhus and 1% to 46.4% for Q fever, based on the literature published with the evidence of isolation, serological, and molecular diagnostics. Search engines Medline/PubMed, Science Direct, ProQuest, and EBSCO were used to retrieve the articles from electronic databases by using appropriate keywords to track the emergence of these rickettsial diseases in India for the period of 1865 to till date. We retrieved 153 published rickettsial articles on hospital-based studies from India that were purely made on the basis of prevalence and the laboratory parameters viz., Weil-Felix test (WF) and Rapid Immunochromatographic tests (RICT) with reference to the gold standard IFA and ELISA. More epidemiological studies are required for epidemic typhus to know the exact prevalence status of this louse-borne rickettsiosis in India. Currently, there is no confirmed specific inflammatory marker for rickettsial diseases. Moreover, serological cross-reactivity is an important aspect, and it should be investigated in endemic areas, there is also a need to include molecular diagnostic techniques for further confirmation in healthcare settings.
Topics: Animals; Humans; India; Prevalence; Rickettsia; Rickettsia Infections; Scrub Typhus; Ticks
PubMed: 38648402
DOI: 10.4103/0972-9062.392255 -
International Journal of Infectious... Jun 2024Crusted scabies (CS, Norwegian scabies) is a severe form of scabies, characterized by hyper-infestation of Sarcoptes scabiei mites. CS is commonly associated with... (Review)
Review
OBJECTIVES
Crusted scabies (CS, Norwegian scabies) is a severe form of scabies, characterized by hyper-infestation of Sarcoptes scabiei mites. CS is commonly associated with immunosuppression but is also reported in overtly immunocompetent individuals. We reviewed immunosuppressive risk factors and comorbidities associated with CS.
METHODS
The National Library of Medicine (PubMed) database was reviewed for patient case reports of CS from January 1998 to July 2023. Two authors screened records for eligibility, extracted data, and one critically appraised the quality of the studies.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42023466126.
RESULTS
A total of 436 records were identified, of which 204 were included for systematic review. From these, 683 CS patients were included. CS impacted both genders equally. Adults (21-59 years) were more commonly affected (45.5%) compared to children (0-20 years, 21%). Corticosteroid use was the most prevalent immunosuppressive risk factor identified (27.7% of all cases). About 10.2% of reports were associated with HIV/AIDS, and 8.5% with HTLV-1 infection. 10.5% of patients were overtly immunocompetent with no known risk factors. Overall, 41 (6.0%) died, many subsequent to secondary bacteremia.
CONCLUSION
This study represents the first systematic review undertaken on immunosuppressive risk factors associated with CS. This provides insights into trends of immunosuppression and mechanisms of CS development.
Topics: Scabies; Humans; Risk Factors; Comorbidity; Female; Male; Adult; Immunocompromised Host; Middle Aged; Young Adult; Adolescent; Child; Animals; Infant; Sarcoptes scabiei; HIV Infections; Child, Preschool; HTLV-I Infections; Immunosuppression Therapy; Infant, Newborn
PubMed: 38570134
DOI: 10.1016/j.ijid.2024.107036 -
PloS One 2020Existing evidence on the relationship between childhood lower respiratory tract infections (LRTI) and the subsequent atopy development is controversial. We aimed to... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Existing evidence on the relationship between childhood lower respiratory tract infections (LRTI) and the subsequent atopy development is controversial. We aimed to investigate an association between viral LRTI at <5 years and the development of atopy at > 2 years.
METHODS
We conducted a search at Embase, Pubmed, Web of Science, and Global Index Medicus. We collected data from the included articles. We estimated the odds ratio and the 95% confidence intervals with a random effect model. We determined factors associated with atopy development after childhood LRTI using univariate and multivariate meta-regression analyses. We recorded this systematic review at PROSPERO with the number CRD42018116955.
RESULTS
We included 24 studies. There was no relationship between viral LRTI at <5 years and skin prick test-diagnosed-atopy (OR = 1.2, [95% CI = 0.7-2.0]), unknown diagnosed-atopy (OR = 0.7, [95% CI = 0.4-1.3]), atopic dermatitis (OR = 1.2, [95% CI = 0.9-1.6]), hyperreactivity to pollen (OR = 0.8, [95% CI = 0.3-2.7]), food (OR = 0.8, [95% CI = 0.3-2.5]), or house dust mite (OR = 1.1, [95% CI = 0.6-2.2]). Although not confirmed in all studies with a symmetric distribution of the 23 confounding factors investigated, the overall analyses showed that there was a relationship between childhood viral LRTI at < 5 years and serum test diagnosed-atopy (OR = 2.0, [95% CI = 1.0-4.1]), allergic rhinoconjunctivitis (OR = 1.7, [95% CI = 1.1-2.9]), hyperreactivity diagnosed by serum tests with food (OR = 5.3, [1.7-16.7]) or inhaled allergens (OR = 4.2, [95% CI = 2.1-8.5]), or furred animals (OR = 0.6, [95% CI = 0.5-0.9]).
CONCLUSION
These results suggest that there is no association between viral LRTI at < 5 years and the majority of categories of atopy studied during this work. These results, however, are not confirmed for the remaining categories of atopy and more particularly those diagnosed by serum tests. There is a real need to develop more accurate atopy diagnostic tools.
Topics: Allergens; Animals; Asthma; Child; Conjunctivitis, Allergic; Dermatitis, Atopic; Dermatophagoides pteronyssinus; Humans; Pollen; Respiratory Tract Infections; Rhinitis, Allergic; Skin Tests; Time Factors
PubMed: 32330171
DOI: 10.1371/journal.pone.0231816 -
Allergy, Asthma, and Clinical... 2020Current guidelines do not recommend performing aeroallergen skin prick testing (SPT) in chronic spontaneous urticaria (CSU). (Review)
Review
Presence of positive skin prick tests to inhalant allergens and markers of T2 inflammation in subjects with chronic spontaneous urticaria (CSU): a systematic literature review.
BACKGROUND
Current guidelines do not recommend performing aeroallergen skin prick testing (SPT) in chronic spontaneous urticaria (CSU).
OBJECTIVE
The objective of this review was to investigate the presence of aeroallergen sensitization and markers of T2 inflammation in subjects with CSU.
METHODS
Systematic literature reviews to identify all studies that evaluated the presence of T2 markers of allergic inflammation in CSU subjects were performed.
RESULTS
In 16 studies that assessed the prevalence of positive SPT to multiple aeroallergens in CSU, 38.5% of CSU subjects had positive SPT. In three controlled studies, 34.2% of CSU subjects had positive SPT to multiple aeroallergens, compared to 13.6% of controls (p = 0.047). In 18 studies that assessed the prevalence of house dust mite (HDM) positive SPT in CSU, 27.5% of CSU subjects had positive SPT. In three controlled studies, 27.5% of CSU subjects had positive SPT to HDM, compared to 2.1% of controls (p = 0.047). Overall, CSU subjects were 3.1 times more likely to be aeroallergen-sensitized (95% CI 1.7-5.8, p = 0.0002) and 6.1 times more likely to be HDM-sensitized (95% CI 3.7-9.9, p < 0.00001) than controls. Mean total serum IgE (tIgE) levels were 238 kU/L and median tIgE levels were 164 kU/L, which was greater than the upper 90 percentile of normal (< 137 kU/L). Compared to healthy controls, CSU subjects were 6.5 times more likely to have IgG autoantibody against FcεR1α (p = 0.001), 2.4 times more likely to have IgG anti-IgE antibody (p = 0.03) and 5 times more likely to have anti-thyroid peroxidase (anti-TPO) antibody (p = 0.02). When corticosteroids were withheld for ≥ 28 days, mean blood eosinophil percentage was elevated at 5.9% (normal < 4%), but other studies reporting absolute count found the mean was in the normal range, 239 L (normal < 400 L).
CONCLUSION
Increased aeroallergen sensitization, tIgE, autoantibodies and blood eosinophil percentage in the CSU subjects indicates the possible importance of T2 inflammation in the pathogenesis of CSU. Further studies may be warranted to determine if specific allergen avoidance, desensitization or improvement in the mucosal allergic inflammation present in asthma and/or rhinitis has any benefit in the management of CSU.
PubMed: 32944029
DOI: 10.1186/s13223-020-00461-x -
The Cochrane Database of Systematic... Jul 2007In infants with a family history of atopy, food allergen avoidance has been advocated as means of preventing the development of atopic disease, when breast-feeding is... (Review)
Review
BACKGROUND
In infants with a family history of atopy, food allergen avoidance has been advocated as means of preventing the development of atopic disease, when breast-feeding is not possible or supplemental feeding is needed. Most infant formulas are based on cow's milk protein. Alternative choices include soya based and hydrolysed cows milk formulas.
OBJECTIVES
To estimate the effect of dietary avoidance of cow's milk protein on the development of asthma or wheeze in children.
SEARCH STRATEGY
We searched the Cochrane database for eligible trials until February 2002. We obtained the full text papers of all abstracts identified as RCTs and two reviewers independently reviewed them.
SELECTION CRITERIA
We included randomised controlled trials involving children with a family history of atopy in at least one first degree relative, if feeding with cow's milk based standard formula was compared to dietary avoidance of cow's milk protein, using soya or other hypoallergenic formula during the initial four months of life or longer.
DATA COLLECTION AND ANALYSIS
Two reviewers extracted data independently. A priori defined subgroups were the types of hypoallergenic artificial feed and dietary restrictions on mother and/or child's diet.
MAIN RESULTS
Six trials used hydrolysed formula for at least four months, in addition to dietary restrictions and in some cases dust-mite reduction measures. The risk of infants experiencing asthma or wheeze during the first year of life was reduced compared to standard cow's milk based formula (Relative Risk 0.40, 95% Confidence Intervals 0.19 to 0.85). Feeding soya-based formula as opposed to standard cow's milk formula did not reduce the risk of having asthma or wheeze at any age.
AUTHORS' CONCLUSIONS
Breast-milk should remain the feed of choice for all babies. In infants with at least one first degree relative with atopy, hydrolysed formula for a minimum of four months combined with dietary restrictions and environment measures may reduce the risk of developing asthma or wheeze in the first year of life. There is insufficient evidence to suggest that soya-based milk formula has any benefit.
Topics: Asthma; Family; Humans; Infant; Infant Food; Infant, Newborn; Milk Hypersensitivity; Milk Proteins; Randomized Controlled Trials as Topic; Respiratory Sounds
PubMed: 17636737
DOI: 10.1002/14651858.CD003795.pub2 -
The Canadian Journal of Infectious... 2011Accurate diagnosis of scabies infection is important for patient treatment and for public health control of scabies epidemics.
BACKGROUND
Accurate diagnosis of scabies infection is important for patient treatment and for public health control of scabies epidemics.
OBJECTIVE
To systematically review the accuracy and precision of history, physical examination and tests for diagnosing scabies.
METHODS
Using a structured search strategy, Medline and Embase databases were searched for English and French language articles that included a diagnosis of scabies. Studies comparing history, physical examination and/or any diagnostic tests with the reference standard of microscopic visualization of mites, eggs or fecal elements obtained from skin scrapings or biopsies were included for analysis. Data were extracted using standard criteria.
RESULTS
History and examination of pruritic dermatoses failed to accurately diagnose scabies infection. Dermatoscopy by a trained practitioner has a positive likelihood ratio of 6.5 (95% CI 4.1 to 10.3) and a negative likelihood ratio of 0.1 (95% CI 0.06 to 0.2) for diagnosing scabies. The accuracy of other diagnostic tests could not be calculated from the data in the literature.
CONCLUSIONS
In the face of such diagnostic inaccuracy, clinical judgment is still practical in diagnosing scabies. Two tests are used - the burrow ink test and handheld dermatoscopy. The burrow ink test is a simple, rapid, noninvasive test that can be used to screen a large number of patients. Handheld dermatoscopy is an accurate test, but requires special equipment and trained practitioners. Given the morbidity and costs of scabies infection, and that studies to date lack adequate internal and external validity, research to identify or develop accurate diagnostic tests for scabies infection is needed and justifiable.
PubMed: 23205026
DOI: 10.1155/2011/698494 -
Parasitology Dec 2020Various treatments are found to be moderately effective in managing Demodex-related diseases except tea tree oil (TTO) and terpinen-4-ol (T4O), which showed superior... (Comparative Study)
Comparative Study
Various treatments are found to be moderately effective in managing Demodex-related diseases except tea tree oil (TTO) and terpinen-4-ol (T4O), which showed superior miticidal and anti-inflammatory effects in numerous clinical studies. Their possible effects include lowering mite counts, relieving Demodex-related symptoms, and modulating the immune system. This review summarizes the current clinical topical and oral treatments in human demodicosis, their possible mechanisms of action, side-effects and resistance in treating this condition. TTO (especially T4O) is found to be the most effective followed by metronidazole, ivermectin and permethrin in managing the disease. This is because TTO has anti-parasitic, anti-bacterial, anti-fungal, anti-inflammatory and wound-healing effects. Furthermore, nanoTTO can even release its contents into fungus and Pseudomonas biofilms. Combinations of different treatments are occasionally needed for refractory cases, especially for individuals with underlying genetic predisposal or are immuno-compromised. Although the current treatments show efficacy in controlling the Demodex mite population and the related symptoms, further research needs to be focused on the efficacy and drug delivery technology in order to develop alternative treatments with better side-effects profiles, less toxicity, lower risk of resistance and are more cost-effective.
Topics: Acaricides; Humans; Mite Infestations; Tea Tree Oil
PubMed: 32772960
DOI: 10.1017/S003118202000150X