Latest research in travel medicine
Friday 3rd November 2023
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Ecological and environmental factors affecting the risk of TBE in Europe- this study starts to identify the changes in climate which is affecting the distribution of ticks associated with TBE in Europe. The findings have shown the presence of key animal species, such as deer and rodents, in forested areas and that of specific climatic conditions, such as high precipitation during the driest months of the year, cold winters, small daily temperature variations and a steep decrease in late summer temperatures increase the risk of TBE to humans.https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2023.28.42.2300121
Atovaquone injection for malaria treatment and prevention- A study from Johns Hopkins and University of Liverpool has highlighted the use of atovaquone injection in malaria. Although on its own atovaquone can present with drug resistance caused by Plasmodium mutation in the body when in the gut of the Anopheles mosquito it destroys the parasite.
Victoria A. Balta et al, Clinically relevant atovaquone-resistant human malaria parasites fail to transmit by mosquito, Nature Communications (2023)
Monday 11th September 2023
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Chikungunya virus- transmission to other cells- early research highlights the findings that chikungunya virus may infect the host cytoskeleton by producing long extensions that make contact with surrounding cells allowing the transmission of the virus. In turn this can shield the virus from the host antibody system. Chikungunya virus cell-to-cell transmission is mediated by intercellular extensions in vitro and in vivo, Nature Microbiology (2023). DOI: 10.1038/s41564-023-01449-0
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Friday 30th June 2023
WHO- Pan American Health organisation Epidemiological Update- Dengue reported with all 4 serotypes, increasing levels of chikungunya and zika.
https://www.paho.org/en/documents/epidemiological-update-dengue-chikungunya-and-zika-10-june-2023
Friday 9th June 2023
Economics of using Wolbachia infected mosquitoes to control dengue- this paper from Vietnam finds that if the reduced dengue levels are sustained for over 10 years then the cost of introduction becomes effective. https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0011356
Review of meningitis carriage and serotypes from Hajj- this paper is a timely reminder that the Hajj is approaching and the entry requirement of a meningitis ACWY vaccine is required. The research found that the carriage was low during the event, however most isolates were resistant to ciprofloxacin, the standard treatment.
Wednesday l7th May 2023
Mosquito Migration- high altitude dispersal patterns of vectors in Africa, highlight that vectors could spread further and quicker due to them riding high altitude winds. https://entomologytoday.org/2023/05/05/mosquito-migration-more-high-altitude-dispersal-disease-vectors-africa-malaria/
Mosquito populations- West Nile Virus vector mosquitoes (Culex) found to be travelling 5-20 kms. https://entomologytoday.org/2023/05/02/mosquito-populations-viruses-linked-distances-synchrony/
Friday 28th April 2023
Mosquito saliva containing components that increase virus infection- A study from US had identified the vesicles contained within mosquito saliva that enhance virus infection following a bite. The study involving dengue infections spread from Aedes species showed that not only was the virus transmitted but also a product (called non-coding RNA) that reduces the human body anti-virus protection systems. https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1011224
Friday 17th March 2023
New drug under trial to treat dengue- first stage trials of a selective drug that is effective against all 4 serotypes of dengue- https://www.jnj.com/janssen-announces-novel-dengue-antiviral-demonstrates-efficacy-in-pre-clinical-data-published-in-nature
Friday 17th March 2023
Effects of dengue serotypes in pregnancy- contracting dengue whilst pregnant can cause a severe reaction particularly with serotypes 1 and 2. https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-023-08051-z
New antimalarial more effective than current treatment- A trial from Liverpool School of Tropical Medicine shows that dihydroartemisinin-piperaquine (DP) is more effective in the prevention of malaria but shows no difference in adverse birth outcomes- https://medicalxpress.com/news/2023-03-antimalarial-effective-current-treatment-adverse.html
Friday 10th February
Malaria- antimalarial monoclonal antibody shows promise in a small study- a small study has shown the benefit of using monoclonal antibody treatment in malaria. A single dose given subcut showed protection against malaria with a suggested period of up to 6 months. This is an improvement on the previous vaccine trials which require 3-4 doses. Longer term trials are required to fully evaluate the length of protection. https://medicalxpress.com/news/2023-01-small-antimalarial-monoclonal-antibody-malaria.html
Latest research shows transfer of immunity for Nipah virus from Mother to child- the highly infectious Nipah virus (40-75% mortality) IgG has been detected in in a child of 1 year, who has never been affected by the disease. The study from Bangladesh concludes the humoral immunity was transferred following the mother’s consumption of raw date palm sap and diagnosed with Nipah virus. http://outbreaknewstoday.com/bangladesh-researchers-transfer-of-immunity-against-nipah-virus-from-mother-to-child-confirmed-for-the-first-time-29319/
Food insecurity and risk of cholera- with continuing outbreak reports of cholera from Nigeria, Ethiopia and Zambia, a recent paper has looked at the link to food insecurity. This looks at the factors and household links. In a cross-sectional survey the dietary choices and food handling behaviours were reviewed. Hunger was associated with 3 behaviours namely, antacid use, consumption of leftover non-reheated food and eating food prepared outside of the home. All were positively associated with cholera, indicating that prevention will need to target all food insecurities to prevent and reduce cholera. https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0010574
13th January 2023
Study finds bacteria living in and on mosquitoes- We are familiar with mosquitoes passing blood borne infections through feeding. However, this latest research indicates that common other bacterial infections such as Rickettsia and Staphylococcus were found on the outside of the feeding mosquitoes. https://www.sciencedaily.com/releases/2022/12/221216153541.htm
Post-exposure rabies prophylaxis- The Lancet reports on that 69% of reports were classed as severe and deviations from recommended practices occurred in 56% of cases. Highlighting the need to rabies awareness, pretravel vaccinations and first aid treatment if exposed.
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(22)00641-7/fulltext
20th December 2022
Predictive indices of Acute Mountain Sickness (AMS)- A small study of military personnel have been measured for physiological and biochemical markers when at high altitude to determine if AMS can be predicted. This study highlights that the measurement of uric acid could be useful indicator. https://www.sciencedirect.com/science/article/pii/S1477893922002526
Vitamin B as a mosquito repellent? - The age-old myth of the effectiveness of vitamin B is assessed and reviewed to establish the validity behind the claims. As expected, no evidence is produced to support the claims first raised 80 years ago.
https://entomologytoday.org/2022/11/21/vitamin-b1-not-mosquito-repellent/
I7.10.2022
The impact of tropical cyclones on incidence of dengue. Cyclones increased levels of dengue within a 4 week lag period, affecting more elderly and male patients.
https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-022-05486-2
Covid-19 vaccination during pregnancy is safe and beneficial.
Lassa virus endemic may expand dramatically. The current isolated areas of Africa may be expanded into central and eastern countries.
Covid-19 Hospitalizations by vaccination status. Report highlights hospitalizations were 10.5 times more in unvaccinated patients and 2.5 times more inpatients who had not received a booster.
https://www.contagionlive.com/view/covid-19-hospitalizations-broken-down-by-vaccination-status
Immunogenicity after pre- and post-exposure rabies vaccination: A systematic review and dose-response meta-analysis- a comparison of different IM and ID schedules used around the world.
https://www.sciencedirect.com/science/article/pii/S0264410X21000396
No significant increase in Guillain-Barré syndrome after COVID-19 vaccination in adults- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9393181/​
Date: 21.9.2022
New Bivalent Covid vaccination
The bivalent omicron-containing vaccine mRNA-1273.214 elicited neutralizing antibody responses against omicron that were superior to those with mRNA-1273, without evident safety concerns.
14.9.2022
(Author notes- new research published this week surveillance, BMJ, NEJM, JTH, TMAID)
Covid-19 Vaccines- Immunity, Variants and Boosters
This forms part of the Epstein lecture and focuses the attention on the current situation to date from a global perspective. The conclusions drawn suggest Covid is now moving into an endemic phase and the current vaccines are less efficient against omicron variant. The future role of studies should be not only the short-term neutralizing antibody titres but to include durability of antibody responses, memory B-cell responses and cross-reactive T-cell responses.
Date: 12.9.2022
(Author notes- new research published this week surveillance, BMJ, NEJM, JTH, TMAID)
Potential treatment for Chagas disease.
University of Georgia has discovered a new anti-parasitic compound (AN15368) that has targets the infecting organism that causes this version of trypansomiasis. Untreated the condition can lead to severe heart damage with current medications having serious side-effects and not very reliable.
https://medicalxpress.com/news/2022-09-potential-treatment-chagas-disease-1.html
Malaria vaccines- Mosquirix and Matrix-M
Announced by GSK, Mosquirix (also known as RTS,S/AS01) was awarded pre-qualification by WHO for moderate to high P. falciparum malaria transmission areas. Trials have shown this to be up to 60% effective
http://outbreaknewstoday.com/malaria-vaccine-mosquirix-awarded-prequalification-by-who-57007/
In the UK, Oxford’s R21/Matrix-M vaccine has shown to be 77% effective and exceeding the WHO roadmap goal of 75%. Results from phase 3 trials are due later this year.
https://medicalxpress.com/news/2022-09-malaria-vaccine-results-mass-rollout.html
New Hepatitis B vaccine
Valneva have developed a new Hepatitis B vaccine, PreHevbri. This has European and UK licensing for 0-1-6 month schedule and benefits from providing a higher proportion of the users with protection at 4 weeks (91%) compared to standard HepB vaccines (76%).