West Nile virus: biology, transmission, clinical manifestations, diagnosis, therapeutic approaches, climatic correlates and prevention

M. Mavrouli1, G. Vrioni1, A. Vlahakis2, V. Kapsimali1, S. Mavroulis3, A. Antypas2, A. Tsakris1
1Department of Microbiology, Medical School, University of Athens, Athens, Greece
23rd Regional Blood Transfusion Center, General Hospital of Athens “G. Gennimatas”, Athens, Greece
3Department of Dynamic Tectonic Applied Geology, Faculty of Geology and Geoenvironment, University
of Athens, Athens, Greece

West Nile virus (WNV) is a mosquito-borne arbovirus of the Flaviviridae family. Transmission to
humans occurs predominantly following a bite from an infected mosquito, principally of the genus
Culex, which acquires virus after feeding on avian amplifying hosts. Most people infected with
WNV remain asymptomatic, and only 20% of infected individuals develop West Nile fever (WNF),
a mild and self-limited flu-like illness of fever. Less than 1% of WNV infections progress to clinical
disease associated with severe neurological manifestations, including aseptic meningitis, encephalitis,
and acute flaccid paralysis. Since its first isolation in the West Nile district of Uganda in
1937, a geographic expansion and westward spread of the virus has occurred during the last 20
years. Until recently, its medical and veterinary health concern was relatively low; however, the
number, frequency and severity of outbreaks with neurological consequences in humans and
horses have lately increased in Europe and the Mediterranean basin. Even though great advances
have been obtained lately regarding WNV infection, and although efficient equine vaccines are
available, no specific treatments or vaccines for human use are on the market. Peak WNV transmission
occurs during mosquitoes’ active period, usually between midsummer and early autumn.
Climatic conditions (temperature and precipitation), landscape features and land-use seem to
react on WNV transmission. This review updates the most recent investigations in different aspects
of WNV life cycle: molecular virology, host range, transmission dynamics, pathogenesis, clinical
manifestations, diagnosis, vaccine development, control, and prevention, and highlights some aspects
that require further research.

Key words
West Nile virus, Culex pipiens,West Nile fever

Influenza virus infection in children with cancer

A. Kafasi, N. Spanakis, G. Vrioni, A. Tsakris
Department of Microbiology, Medical School, University of Athens, Athens, Greece

Influenza virus infection can cause serious complications in children who are immunosuppressed
concerning their medical treatment against cancer. The increased risk of infection in this group
of patients may be due to either the disease itself or to their immunosuppression as a result of
chemotherapy. Influenza virus infections present in the form of annual infections and may cause
interruption of the cancer treatment for up to several weeks. In patients with cancer, immunization
via vaccine has been shown to provide protection against several virus infections at similar
levels to those of healthy individuals. This evidence can be translated into reduced duration and
severity of the infection and potential improvement in patients’ morbidity and mortality. Immune
responses depend on the time of the immunization via vaccine, concerning the time that
has passed since the last chemotherapy treatment. It has been shown that patients receiving
chemotherapy develop weaker immune responses compared with those who have completed
chemotherapy, as well as with healthy people. However, few data are available for cancer patients
who are in childhood, as the groups of patients are heterogeneous with regard to underlying
malignancy, the type of chemotherapy, the dose, the time and the route of administration of influenza
vaccine. As for the vaccine’s composition, the circulating human influenza viruses are
subject to antigenic changes requiring annual adjustment of the composition of the vaccine.
We can underline that the vaccine containing inactivated virus strains contains no risk to cause
outbreak or secondary complications and is considered safe for administration to immunocompromised
individuals, even though these are children.

Key words
influenza virus, cancer, chemotherapy, children, vaccination

Differential diagnosis between microorganisms of the genus Kocuria and Staphylococcus

D. Dimitriadi1, E. Charvalos2
1Medical Diagnostics and Biotechnology Laboratories S.A. (InVitroLabs), Peristeri, Attiki, Greece,
2Iaso Group of Hospitals, Marousi, Attiki, Greece

Microorganisms of the genus Kocuria are Gram-positive coccoid bacteria, which were previously
classified in the genus Micrococcus. They are commensals of the skin and mucosa and cause infections
mainly to immunocompromised hosts. In recent years there is an increase of reports regarding
infections caused by microorganisms of the genus Kocuria, probably because of improved identification
systems, vigilance of microbiologists and longer survival of immunocompromised patients.
However, the prevalence of human infections caused by Kocuria species is underestimated, as commonly
used phenotypic assays are known to misidentify Kocuria isolates as Staphylococcus.

Key words
kocuria, staphylococcus, laboratory diagnostics

The evolution of the Greek Microbiology through a bibliometric study of the publications of Acta Microbiologica Hellenica (1956-2014): Part A (1956-1979)

C. Tsiamis1, G. Vrioni1, E. Vogiatzakis2, A. Tsakris1
1Department of Microbiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
2Department of Microbiology, General Chest Hospital “Sotiria”, Athens, Greece

The aim of the study is the presentation of the evolution of Greek Microbiology through the articles
of the Official Journal of the Hellenic Microbiological Society, “Acta Microbiologica Hellenica”.
The study presents the articles in the spectrum of the infectious diseases of every decade with
the help of indexing and bibliometrics of 1,558 articles during the period 1956-2014. During the
period 1956-1969, the articles were identified with the problems of Public Health in Greece, such
as poliomyelitis, and the international microbiological research. Also, during this period the main
interest of the articles are the Gram-negative aerobic bacteria and Gram-positive cocci. The microorganisms
primarily identified were Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa,
Shigella spp., Proteus vulgaris and Neisseria gonnorheae. The study of Gram-negative aerobic
bacteria and Gram-positive cocci will increase during the period 1970-1979. The interest of the
microbiologists contain mainly microorganisms such as Staphylococcus aureus, Staphylococcus
epidermidis, Clostridium perfringens and Neisseria meningitidis. During 1970s, we can detect the
first articles about the risks of the nosocomial infections in the Greek hospitals for microorganisms
such as Staphylococcus aureus, Streptococcus spp., Escherichia coli, Klebsiella pneumonia, Proteus
vulgaris and Pseudomonas aeruginosa. The interest of the Greek microbiologists seems to be intensive
for another communicable disease: hepatitis. During the period 1971-1979, several articles
were identified for Picornaviridae and Orthomyxoviridae. According to our findings, it seems that
the period 1956-1979, the journal follows the scientific timeliness and the serious infectious diseases
of the country.

Key words
Acta Microbiologica Hellenica, bibliometrics,history of microbiology

Necrotizing pneumonia due to Rhodococcus equi in an HIV patient: a case report and review of the literature

K. Avgoulea1, O. Zarkotou1, G. Chrysos2, V. Mamali1, A. Gerogiokas1, J. Papaparaskevas3,
A. Tsakris3, K. Themeli-Digalaki1
1Department of Microbiology General Hospital of Piraeus “Tzaneio”, Piraeus, Greece
2Infectious Diseases Unit, General Hospital of Piraeus “Tzaneio”, Piraeus, Greece
3Department of Microbiology Medical School, University of Athens, Athens, Greece

Rhodococcus equi infection in humans was first reported in 1967. Since the advent of the AIDS
epidemic, the reported cases of human infection increased dramatically and Rhodococcus equi
has become an important opportunistic pathogen in immunocompromised patients. The presented
case is a necrotizing pneumonia in a 45-year-old HIV-positive man who responded well
to clarythromycin and rifampicin / isoniazid. The aim of this report is to increase physician awareness
so as to suspect a Rhodococcus equi infection and to render the microbiologists more

Key words
Rhodococcus equi, necrotizing pneumonia,opportunistic pathogen, HIV