#14,594
Although it varies from month to month, about 10% of the blog posts at AFD are reviews of recently published scientific papers, very nearly all of which focus on infectious diseases. While they are often overshadowed by outbreak reports, and generally take hours and more effort to write, they are my favorite part of blogging.
During March of 2019, we were dealing with a prolonged and increasingly severe flu season, a spring surge of MERS cases in Saudi Arabia, a new reassorted H5N2 virus in Egypt, ASF raging in Vietnam, and the CDC Issued a HAN update on Hepatitis A outbreaks across multiple states, but we still had time to look at:Several early reports on Baloxivir resistant flu virus transmission from Japan. Baloxavir marboxil (trade name Xofluza®) was approved in the United States only in October 2018, (see FDA Approval Of Xofluza : A New Class Of Influenza Antiviral), but had been in use in Japan for about a year.
While we would learn more about the fitness of these resistant viruses in the months to come (see November's Nature MicroB.: Influenza A Variants with Reduced Susceptibility to Baloxavir Are Fit & Transmit Easily), the first clues came from a bulletin published by Japan's National Institute of Infectious Diseases (NIID) in mid-March and a Rapid Communications from Eurosurveillance published 10 days later.
In Two Studies On The Recent Evolution Of HPAI H5 Viruses In The Middle East we looked at both H5N1 and H5N8.
While avian flu gets the biggest headlines because of its high mortality in humans, swine influenza viruses (H1, H2 & H3) are probably more likely to jump to humans and spark a pandemic (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?).
A little over three years ago, Chen Hualan - director of China's National Avian Influenza Reference Laboratory - pegged the EA (Eurasian Avian-like) H1N1 swine virus (EAH1N1) as having perhaps the greatest pandemic potential of any of the novel viruses in circulation.
Japan NIID Reports 3 Xofluza Resistant Flu Viruses In Untreated Patients
This first report is machine translated from Japanese, and so the syntax suffers a bit, but it described 3 H3N2 flu cases (all children) discovered to carry the PA138T resistance mutation for Baloxivir, despite not having received the drug, suggested community transmission.
Eurosurveillance: H3N2 Virus With Reduced Susceptibility to Baloxavir - Japan, Feb 2019
This second report detailed the detection of Baloxivir resistant flu viruses in 9 children - some of whom had received the drug, while others had not - over the winter in Japan.
You'll also find another follow up to this story in August in (EID Journal: H-2-H Transmission Of A(H3N2) with Reduced Susceptibility to Baloxavir, Japan), which reported:
During the 2018–19 influenza season in Japan, we detected 32 mutant influenza A(H3N2) viruses carrying various types of PA I38 substitutions, 4 of which were isolated from children < 12 years of age without prior baloxavir exposure.
While new avian flu activity has been greatly subdued the past year or two, research continues to emerge, and we looked at three HPAI H5 studies in March.
Emerg. Microbes & Inf.: H5N1 Exposure & Human Seroconversion - Cameroon.
Despite some anecdotal reports to the contrary, human infection with avian flu in Africa - outside of Egypt - has only rarely been reported, despite the presence of HPAI H5N1 in poultry. Whether this is due to minor variations in the local strain (see Differences In Virulence Between Closely Related H5N1 Strains), or simply a lack of testing and reporting, remains a mystery.
While not a slam dunk, this study found limited evidence of seroconversion among 131 poultry workers tested, finding as many as 12% might have been exposed (low, but detectable titers), with 1.5% showed convincing levels of H5 antibodies.
In Two Studies On The Recent Evolution Of HPAI H5 Viruses In The Middle East we looked at both H5N1 and H5N8.
Between November 2014 and May 2015 Egypt (and the world) saw its largest human outbreak of H5N1, and while the full extent of the outbreak may never be known, at least 160 people were infected (see EID Dispatch: Increased Number Of Human H5N1 Infection – Egypt, 2014-15).
The first study, published in Hosts and Viruses, looks at changes in Egypt's H5N1 virus since that outbreak, and calls into question the effectiveness of Egypt's poultry vaccination program. Topics we've covered before (see Efficacy Of AI Vaccines Against The H5N8 Virus in Egypt and Egypt: A Paltry Poultry Vaccine).
Evolutionary Analysis and Phylodynamics of Avian Influenza Virus H5N1 between 2015 and 2016 in Egypt
Osama Elshazly 1 , AbdelSatar Arafa 1 , Mohammed A. Rohaim 2 , Ismaeil M. Reda 2 and Hussein A. Hussein 2*
(Excerpt)
The wide circulation of the 2.2.1.2 subclade, carrying triple mutations (120, 129Δ, I151T) associated with increased binding affinity to human receptors, is an alarming finding with public health importance.
The second report published by Comparative Immunology, Microbiology and Infectious Diseases, provides a genomic characterization of an H5N8 virus isolated from a crow in Iran, a part of the world from which we get limited scientific data.
Full genome characterization of Iranian H5N8 highly pathogenic avian influenza virus from Hooded Crow (Corvus cornix), 2017: The first report
Highlights(EXCERPT)
- Identification of H5N8 highly Pathogen Avian Influenza Virus from Hooded crow (Corvus cornix) in a national park located at Esfehan province in Iran.
- Based on HA sequencing results, it belongs to 2.3.4.4 clade, and the cleavage site is (PLREKRRKR/G).
- Complete genome characterization of this virus revealed probable reassortment of the virus with East-Asian low-pathogenic influenza viruses.
- A mutation at antibody binding site of hemagglutinin A201E of Aghakhan revealed the probable initialization for antigenic drift of this virus.
- Phenotypic markers related to the increased potential for transmission and pathogenicity to mammals were observed.
Our study provides evidence for fast and continuing reassortment of H5 clade 2.3.4.4 viruses, that might lead to changes in virus structural and functional characteristics such as the route and method of transmission of the virus and virus infective, pathogenic and zoonotic potential
As we've seen previously, clade 2.3.4.4. H5 reassorts easily with other viruses, and continues to pick up signs of mammalian adaptation.
Over the past decade we've also looked at numerous studies on neurological sequelae following viral infection, including in utero, and while the evidence hasn't always been compelling, the unexpected number of birth defects stemming from maternal Zika infection has added new fuel to the fire.
Over the past decade we've also looked at numerous studies on neurological sequelae following viral infection, including in utero, and while the evidence hasn't always been compelling, the unexpected number of birth defects stemming from maternal Zika infection has added new fuel to the fire.
JAMA Psych: Long-term Risk of Neuropsychiatric Disease After Exposure to Infection In Utero
Key Points
Question Does exposure to maternal infection during pregnancy increase the long-term risk for major psychiatric disorders in the child?
Findings In this Swedish population-based cohort study of children born between 1973 and 2014, exposure to infection in pregnancy significantly increased the risk for autism spectrum disorder and depression.
Meaning Maternal infection during pregnancy may be responsible for some portion of autism and depression in childhood and adulthood among the exposed offspring.
While avian flu gets the biggest headlines because of its high mortality in humans, swine influenza viruses (H1, H2 & H3) are probably more likely to jump to humans and spark a pandemic (see Are Influenza Pandemic Viruses Members Of An Exclusive Club?).
A little over three years ago, Chen Hualan - director of China's National Avian Influenza Reference Laboratory - pegged the EA (Eurasian Avian-like) H1N1 swine virus (EAH1N1) as having perhaps the greatest pandemic potential of any of the novel viruses in circulation.
Our next paper provides a lengthy, and quite detailed review of swine-origin H1 variant flu viruses, and their pandemic potential - written by researchers at the CDC's NCIRD - and was published in Tropical Medicine and Infectious Diseases.
While their consensus is that these swine-variant viruses still require additional adaptation to human physiology in order to spark a pandemic, recent history has shown the ability of swine-origin viruses to evolve and adapt to humans.
You'll find excerpts from the WHO's press release, and a link to the 31 page PDF file, in:
While their consensus is that these swine-variant viruses still require additional adaptation to human physiology in order to spark a pandemic, recent history has shown the ability of swine-origin viruses to evolve and adapt to humans.
Trop. Med & Inf. Dis.: Mammalian Pathogenicity and Transmissibility of H1 Swine Variant Influenza
And last, but not least, in March the World Health Organization released a new global influenza strategy for the decade ahead (2019-2030), with the the stated goals of preventing seasonal influenza, controlling the zoonotic spread of influenza to humans, and preparing for the next influenza pandemic.
WHO Global Influenza Strategy 2019-2030
