INTRODUCTION
Dengue fever (DF) is a tropical disease caused by the dengue virus
(DENV) belonging to the Flaviviridae family 1.
Considered a zoonotic arbovirus, it is mainly transmitted by the female
mosquitoes of the Aedes aegypti species, and to a lesser extent
by other species such as Aedes albopictus, Aedes polynesiensis,
Aedes scutellaris 1. Humans are the main reservoir
and host causing global spread and therefore it has been a major public
health concern, with an incidence increase of 30-fold in the last five
decades 2. It was estimated from de 2013 Global Burden
of Diseases (GBD) that, in that year, there were 58ยท40 million dengue
cases in 141 countries, with a 18% hospital admission rate and over
13,000 deaths. The annual global cost with the disease was 8,9 billion
dollars 3.
DF is a systemic and dynamic infection with a broad clinical spectrum of
manifestations that may range from asymptomatic disease to serious and
life-threatening hemorrhagic syndromes, known as dengue hemorrhagic
fever (DHF), and dengue shock syndrome (DSS). Both these phases are
considered complications, and uncomplicated cases are characterized by
self-limited fever, lasting usually for 5โ7 days. Dengue can be
debilitating during the acute illness stage and classical clinical
features in adults include high fever (usually biphasic), severe
headache, retroorbital pain, myalgia, arthralgia, nausea, vomiting, and
petechiae. Leukopenia and thrombocytopenia are frequent findings2. No effective therapy is currently available and
treatment is purely symptomatic, requiring a high level of patient care.
Patients can be hospitalized to facilitate fluid replacement and blood
transfusions, when indicated. Severe cases occur in approximately
500,000 people/year and present a mortality rate of up to 10% for
hospitalized patients and 30% for non-hospitalized patients4.
A single-stranded RNA virus, DENV has a positive-sense genome,
containing approximately 10,700 bases. This genome contains a single
open reading frame (ORF) which, when cleaved, gives rise to three
structural proteins, capsid [C], pre-membrane [prM], and
envelope [E], and seven non-structural proteins (NS1, NS2A, NS2B,
NS3, NS4A, NS4B, NS5) 5โ7. The various genotypes of
DENV arise due to the action of an RNA polymerase that lacks
proofreading activity, resulting in at least one new mutation being
produced with each replication of its genome 7,8.
About 1,000 years ago, it is estimated that an infectious cycle between
non-human primates and mosquitoes gave rise to the four serotypes of
dengue virus as they are known today and they share approximately 65%
amino acid sequence similarity. The first time the virus was isolated,
in 1943 in Japan, was named DENV1 (with 5 genotypes) and this same
serotype was reported in the Americas in 1977 and in Africa in 19848,9. Approximately 400โ600 years ago, DENV2 (with 5
genotypes) diverged from the sylvatic ancestor and was first isolated in
Hawaii in 1945, in 1964 in Africa and 1953 in the Americas9,10. In 1956, DENV3 (with 4 genotypes) and DENV4
(with 4 genotypes) were first reported in Asia (Philippines and
Thailand). DENV3 arrived in 1962 in Asia, in 1963 in the Americas and in
1984 in Africa. DENV4 had its report not as faithful as it happened with
the other serotypes so, it was not reported until 1981 in Americas9,11,12.
These four serotypes are genetically similar and share approximately
65% of their genomes but each dengue virus serotype shows antigenic
differences which often have spatial and temporal disjunct
distributions. One genotype of one serotype can persist for many years
in a given geographic region and then die out and even be replaced by a
new genotype or lineage but still cause very similar disease13,14 in humans lineage replacement events had several
explanations: a) the stochastic nature of DENV transmission;
b)variations in conditioning within a population; c) increased viremia
in the human host are cited as reasons for these antigenic differences;
d) Co-circulation of multiple dengue serotypes, however, epidemiological
studies have shown that immune enhancement is also a strong line of
evidence 12,15,16.
The dengue fever is a serious public health problem in many countries
around the world, and the lack of specific treatments and effective
vaccines makes disease control more difficult. In addition, the lack of
basic infrastructure in growing population areas, such as sanitation,
garbage collection, water treatment, and sewage treatment, creates an
environment conducive to the proliferation of the dengue mosquito.
Although awareness campaigns, environmental cleanup and sanitation, and
case monitoring can help reduce the incidence of the disease, ongoing
research is essential to better understand the pathogenesis of the
disease, the factors that affect the transmission of the virus, and how
environmental factors can influence mosquito control. This research is
crucial to develop more effective strategies for the prevention,
diagnosis, and treatment of dengue 7,17,18.
The present study evaluated and reviewed the temporal spreading and
evolution of dengue virus serotypes worldwide by Bayesian method
evaluating 1,581 whole genome sequences (WGS) of dengue virus obtained
between January 1944 to July 2022.