Multidrug resistant 2009 A/H1N1 influenza clinical isolate with a neuraminidase I223R mutation retains its virulence and transmissibility in ferrets

Only two classes of antiviral drugs, neuraminidase inhibitors and adamantanes, are approved for prophylaxis and therapy against influenza virus infections. A major concern is that influenza virus becomes resistant to these antiviral drugs and spreads in the human population. The 2009 pandemic A/H1N1 influenza virus is naturally resistant to adamantanes. Recently a novel neuraminidase I223R mutation was identified in an A/H1N1 virus showing cross-resistance to the neuraminidase inhibitors oseltamivir, zanamivir and peramivir. However, the ability of this virus to cause disease and spread in the human population is unknown. Therefore, this clinical isolate (NL/2631-R223) was compared with a well-characterized reference virus (NL/602). In vitro experiments showed that NL/2631-I223R replicated as well as NL/602 in MDCK cells. In a ferret pathogenesis model, body weight loss was similar in animals inoculated with NL/2631-R223 or NL/602. In addition, pulmonary lesions were similar at day 4 post inoculation. However, at day 7 post inoculation, NL/2631-R223 caused milder pulmonary lesions and degree of alveolitis than NL/602. This indicated that the mutant virus was less pathogenic. Both NL/2631-R223 and a recombinant virus with a single I223R change (recNL/602-I223R), transmitted among ferrets by aerosols, despite observed attenuation of recNL/602-I223R in vitro. In conclusion, the I223R mutated virus isolate has comparable replicative ability and transmissibility, but lower pathogenicity than the reference virus based on these in vivo studies. This implies that the 2009 pandemic influenza A/H1N1 virus subtype with an isoleucine to arginine change at position 223 in the neuraminidase has the potential to spread in the human population. It is important to be vigilant for this mutation in influenza surveillance and to continue efforts to increase the arsenal of antiviral drugs to combat influenza.     

Plasma Levels of Inter-α Inhibitor Proteins in Children with Acute Dengue Virus Infection

Background

Inter-α inhibitor proteins (IaIp) belong to a family of protease inhibitors that are involved in the haemostatic and the vascular system. Dengue viruses (DENV) infections are characterized by coagulopathy and increased vascular permeability. In this study we measured the concentration of IaIp during DENV infections and evaluated its potential as a biomarker.

Methods and Findings

Concentrations of IaIp were measured in patients with acute DENV infections using a quantitative, competitive enzyme linked immunoassay. Concentrations of IaIp measured in pediatric patients suffering from severe DENV infections were significantly lower than in healthy controls.

Conclusions

This is the first report to demonstrate changes in concentration of IaIp during viral infections. The data also highlight the potential of IaIp as a biological marker for severity of DENV infections.     

Serologic survey for selected viral pathogens in free-ranging endangered European mink (Mustela lutreola) and other mustelids from south-western France

To investigate the possible role of selected pathogens in the decline of endangered European mink (Mustela lutreola) populations and the potential for these pathogens to affect mink survival, a serologic survey was conducted using serum samples collected from March 1996 to March 2003 in eight departments of south-western France. In total, 481 free-ranging individuals of five mustelid species (including the European mink) were tested. Sympatric mustelids can serve as sentinels to determine the presence of antibodies to viruses in the study area that could potentially infect mink. Antibodies to Canine distemper virus (CDV) were detected in all species; 9% of 127 European mink, 20% of 210 polecats (Mustela putorius), 5% of 112 American mink (Mustela vison), 33% of 21 stone marten (Martes foina) and 5% of 20 pine marten (Martes martes). Antibody prevalence was significantly higher in stone marten and polecats, possibly because their ranges overlap more closely with that of domestic species than that of the other species tested. Antibodies to Canine adenovirus were detected in all species but the pine marten; antibody prevalence estimates ranging from 2% to 10%. Antibodies to canine parainfluenza virus were detected in 1% of European mink, 1% of American mink and 5% of tested polecats but were not detected in Martes species. Antibodies to Rabies virus (RV) were detected in three animals, possibly because of interspecies transmission of bat lyssaviruses as the sampling area is considered to be free of RV, or to a lack of test specificity, as antibody titers were low. The high antibody prevalence to potentially lethal CDV suggests that this pathogen could have significant effects on the free-ranging populations and has implications for the conservation efforts for the endangered European mink.     

Differential Expression of the Middle East Respiratory Syndrome Coronavirus Receptor in the Upper Respiratory Tracts of Humans and Dromedary Camels

Middle East respiratory syndrome coronavirus (MERS-CoV) is not efficiently transmitted between humans, but it is highly prevalent in dromedary camels. Here we report that the MERS-CoV receptor—dipeptidyl peptidase 4 (DPP4)—is expressed in the upper respiratory tract epithelium of camels but not in that of humans. Lack of DPP4 expression may be the primary cause of limited MERS-CoV replication in the human upper respiratory tract and hence restrict transmission.     

Investigation into diseases in free-ranging ring-necked pheasants (<Emphasis Type="Italic">Phasianus colchicus</Emphasis>) in northwestern Germany during population decline with special reference to infectious pathogens

The population of ring-necked pheasants (Phasianus colchicus) is decreasing all over Germany since the years 2008/2009. Besides impacts of habitat changes caused by current rates of land conversion, climatic influences or predators, a contribution of infectious pathogens needs also to be considered. Infectious and non-infectious diseases in free-living populations of ring-necked pheasants have been scarcely investigated so far. In the present study, carcasses of 258 deceased free-ranging pheasants of different age groups, predominantly adult pheasants, collected over a period of 4 years in the states of Lower Saxony, North Rhine–Westphalia and Schleswig-Holstein, were examined pathomorphologically, parasitologically, virologically and bacteriologically, with a focus set on infectious pathogens. A periocular and perinasal dermatitis of unknown origin was present in 62.3% of the pheasants. Additional alterations included protozoal cysts in the skeletal musculature (19.0%), hepatitis (21.7%), enteritis (18.7%), gastritis (12.6%), and pneumonia (11.7%). In single cases, neoplasms (2.6%) and mycobacteriosis (1.7%) occurred. Further findings included identification of coronaviral DNA from trachea or caecal tonsils (16.8%), siadenoviral DNA (7.6%), avian metapneumoviral RNA (6.6%), and infectious bursal disease viral RNA (3.7%). Polymerase chain reaction (PCR) on herpesvirus, avian influenza virus (AIV), paramyxovirus type 1 (PMV-1), avian encephalomyelitis virus (AEV), and chlamydia were negative. Based on the present results, there is no indication of a specific pathogen as a sole cause for population decline in adult pheasants. However, an infectious disease can still not be completely excluded as it may only affect reproduction effectivity or a certain age group of pheasants (e.g., chicks) which were not presented in the study.     

MAPK and PKC activity are not required for H(2)O(2)-induced arterial muscle contraction

H(2)O(2)-induced pulmonary arterial smooth muscle (PASM) contractions are independent of Ca(2+) and myosin light chain phosphorylation. The purpose of this study was to determine whether mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK) 1 and ERK2, or protein kinase C (PKC) activation is required for H(2)O(2)-induced contraction. Porcine PASM strips were stimulated with 1 mM H(2)O(2), 120 mM KCl, or 10 microM phorbol myristic acetate and freeze clamped at various times during the contractions. Changes in relative amounts of tyrosine/threonine phosphorylated MAPK compared with total MAPK were measured. MAPK tyrosine phosphorylation levels increased in correlation with tension development. However, 50 microM PD-98059, a MAPK/ERK kinase-MAPK kinase blocker, reduced MAPK phosphorylation below resting levels, even though the magnitude of the isometric tension development was unaltered. Freeze-clamped PASM strips were placed in a PKC activity assay buffer containing (32)P and CaCl(2) to measure the total myelin basic protein phosphorylation. The data show that: 1) the time courses of PKC activity and force produced in response to H(2)O(2) do not correlate, and 2) MAPK activation may be a concurrent event with, or a consequence of, tension development in response to a variety of agonists but is not responsible for contractions to H(2)O(2), high K(+), or phorbol esters.     

CCR5, GPR15, and CXCR6 are major coreceptors of human immunodeficiency virus type 2 variants isolated from individuals with and without plasma viremia

Human immunodeficiency virus type 2 (HIV-2) is generally considered capable of using a broad range of coreceptors. Since HIV-2 variants from individuals with nonprogressive infection were not studied previously, the possibility that broad coreceptor usage is a property of variants associated with progressive infection could not be excluded. To test this, we determined the coreceptor usage of 43 HIV-2 variants isolated from six long-term-infected individuals with undetectable plasma viremia. Using GHOST indicator cells, we showed for the first time that the only coreceptors efficiently used by low-pathogenic HIV-2 variants are CCR5, GPR15 (BOB), and CXCR6 (BONZO). Surprisingly, control HIV-2 variants (n = 45) isolated from seven viremic individuals also mainly used these three coreceptors, whereas use of CCR1, CCR2b, or CCR3 was rare. Nearly a quarter of all HIV-2 variants tested could infect the parental GHOST cells, which could be partially explained by CXCR4 usage. Use of CXCR4 was observed only for HIV-2 variants from viremic individuals. Thirty-eight variants from aviremic and viremic HIV-2-infected individuals were additionally tested in U87 cells. All except one were capable of infecting the parental U87 cells, often with high efficiency. When virus production in parental cells was regarded as background in the coreceptor-transduced cell lines, the results in U87 cells were largely in agreement with the findings in GHOST cells. HIV-2 isolates from aviremic individuals commonly use as coreceptors CCR5, GPR15, and CXCR6, as well as an unidentified receptor expressed by U87 cells. Broad coreceptor usage, therefore, does not appear to be associated with pathogenicity of HIV-2.     

Serologic survey for selected virus infections in polar bears at Svalbard

Polar bears (Ursus maritimus) were chemically immobilized and sampled at Svalbard, Norway, and on the pack ice in the Barents Sea from late March to mid-May between 1990 and 1998. Plasma samples were tested for the presence of antibodies to canine distemper virus (CDV), calicivirus, phocid herpesvirus type 1 (PhHV-1), and rabies virus. A seroprevalence of 8% to CDV and 2% to calicivirus were found, whereas no antibodies were detected against PhHV-1 or rabies virus. This serologic survey indicates that polar bears in this region are exposed to morbillivirus and calicivirus, although the nature of these viruses and infections are unknown. Morbillivirus and calicivirus are potential pathogens in seals, but it is unknown whether they may cause health problems in polar bears.