Nucleic Acid-based Diagnosis and Epidemiology of Infectious Diseases

In this chapter, the immense contribution of nucleic acid discovery to the diagnosis and molecular epidemiology of pathogenic microorganisms and its relevance for veterinary and human health will be discussed. The development of nucleic acid detection, amplification, and sequencing techniques, principally after the introduction of polymerase chain reaction (PCR), allowed the improvement of different strategies to diagnose and to quantify infectious microbiological agents in a variety of organisms and biological samples. Pos-PCR associated techniques such as fragment enzyme restriction and sequence analysis permit the determination of nucleic acid sequence diversity to detect drug resistance, to associate pathogen genetic markers with disease outcome, and to predict temporal and spatial distribution of microorganisms which can be used to prevent and treat infectious diseases efficiently

Severe visceral leishmaniasis and COVID-19 coinfection in an immunosuppressed patient

Visceral leishmaniasis (VL) is an opportunistic disease in immunosuppressed individuals, who may present severe clinical conditions, such as the ones described in this patient. She lived in an endemic region for VL, and was possibly infected with L. (L.) infantum chagasi through the bite of a contaminated sand fly. This initial infection has triggered a pemphigus vulgaris condition by immunogenic proteins present in the mosquito's saliva. The immunosuppression caused by the use of high doses of corticosteroids to control the disease promoted a severe VL condition, with hepatosplenomegaly, thrombocytopenia and hemorrhages, requiring hospitalization and the onset of a subsequent SARS-CoV-2 infection. Due to the intensity of clinical manifestations related to VL, aggravated by COVID-19, she died two days after admission to the Clinical Hospital of Marilia Medical School (HC–Famema)

Chitinase from Basal Trypanosomatids and Its Relation to Marine Environment: New Insights on <em>Leishmania</em> Genus Evolutionary Theories

Leishmaniasis, an infectious disease that affects humans, domestic dogs, and wild animals, is caused by 20 of the 53 Leishmania genus species and is transmitted by sandflies. Despite its significant impact, the disease is often neglected. Leishmania genus, belong to Trypanosomatide Family and Kinetoplastida Order, are grouped in five subgroups according to biogeographic and evolution history of parasites and hosts. The GH18 Leishmania chitinase is encoded by a specie-specific single copy gene, conserved in basal groups of trypanosomatids, and is absent in the genus Trypanosoma. Preservation of the chitinase genomic locus in the aquatic free-living protozoan Bodo saltans, discloses a primitive common origin. Trypanosomatid chitinase amino acid sequence comparative analysis revealed high similarity with chitinase from sea living prokaryotes and protozoan microorganisms, indicating a probable marine origin. Amino acid sequence comparative analysis revealed that perhaps the trypanosomatid chitinase derived from a water living Kinetoplastida ancestor and its phylogenetic reconstruction corroborates the Supercontinent Origins theory for Leishmania. The chitinase-encoding gene was effective for differential molecular diagnosis among Leishmania clinical important species worldwide

Novel Single Hematophagous Insect RNA Detection Method Supports Its Use as Sentinels to Survey Flaviviruses Circulation

Anthropogenic actions, including deforestation, disorganized urbanization, and globalization, contribute to emergence and reemergence of arboviruses worldwide, where Flavivirus is the most prevalent, and its continuous monitoring can help in preventive control strategies. Thus, the aim of this study was to detect flavivirus RNA in single hematophagous insects, which are used as sentinels. Total RNA was extracted from six Aedes aegypti stored since 2003 and from 100 Culicidae and collected through CDC trap in a public park of a Brazilian Northwest city of São Paulo State. Flavivirus was detected through RT/PCR targeting 230–250 bp of the RNA polymerase coding sequence (NS5). PCR amplicons were sequenced by Sanger method, used in comparative analysis over Basic Local Alignment Search Tool (BLAST) in GenBank, and subjected to Neighbor-Joining phylogenetic analyses. Efficiency of Flavivirus diagnosis was confirmed by detection of Dengue virus serotype 2 in Ae. aegypti. From the 100 collected insects, 19 were positive for Culex flavivirus (CxFV). NS5 partial sequence phylogenetic analysis clustered all CxFV in one branch separated from vertebrate flaviviruses, being applicable to the identification of Flavivirus species. The dipteran RNA extraction methodology described in this work supports detection of flaviviruses in single insects maintained in 80% ethanol, which can be used to constant arbovirus surveillance

Dengue - Immunopathology and Control Strategies

This edited book Dengue - Immunopathology and Control Strategies contains eight chapters divided in three sections that underline important aspects of dengue virus, the most prevalent and life-threatening arbovirus in the world, including virus replication cycle and pathology, diagnostic methods, and control. The first section brings knowledge on basic aspects of dengue virus replication which can be associated to its immunopathology. The second section includes two chapters on dengue diagnosis and emphasizes that in spite of the many scientific efforts, this subject continues to be a drawback in the disease control. Vector-based control strategies are discussed in the third section which also contains a chapter on regulation of dengue vaccines and the experience of Mexico in the implementation of the unique registered dengue vaccine

Perspectives in the control of infectious diseases by transgenic mosquitoes in the post-genomic era: a review

Arthropod-borne diseases caused by a variety of microorganisms such as dengue virus and malaria parasites afflict billions of people worldwide imposing major economic and social burdens. Despite many efforts, vaccines against diseases transmitted by mosquitoes, with the exception of yellow fever, are not available. Control of such infectious pathogens is mainly performed by vector management and treatment of affected individuals with drugs. However, the numbers of insecticide-resistant insects and drug-resistant parasites are increasing. Therefore, inspired in recent years by a lot of new data produced by genomics and post-genomics research, several scientific groups have been working on different strategies to control infectious arthropod-borne diseases. This review focuses on recent advances and perspectives towards construction of transgenic mosquitoes refractory to malaria parasites and dengue virus transmission

Aphrophila chilena.

<p>Habitus in lateral view before (a) and after (b) clarification; head in lateral view before (c) and after clarification (d).</p

Spatio-temporal distribution of human American visceral leishmaniasis in the Western region of Sao Paulo State, from 2004 to 2018

Leishmaniasis comprises a group of zoonotic diseases caused by protozoa belonging to the Leishmania genus, noting that the visceral form is the most severe and lethal, if untreated. Nowadays visceral leishmaniasis is widespread in Brazil and the Adamantina microregion, located in the west of Sao Paulo State, has been affected by Human American Visceral Leishmaniasis (HAVL) since 2004. We evaluated the epidemiological profile of HAVL in the Adamantina microregion through a Geographic Information Systems (GIS) and established its incidence rate by location and time. Notified cases were provided by the Sao Paulo State Epidemiological Surveillance Center. Home addresses of patients who tested positive to HAVL were converted into geographic coordinates through the Google Geocoding Application Programming Interface submitted to ArcMap 10.5 System for georeferencing. Kernel spatial analyses were performed to obtain the incidence distribution and the total area involvement rate. From 2004 to 2018, 325 cases of HAVL were diagnosed in 11 of the 12 municipalities belonging to the of Adamantina microregion. The disease has disseminated to the Northwest and East-Southeast directions, taking place along the Comandante Joao Ribeiro de Barros highway, with higher incidences rates in the municipalities where the highway passes. HAVL incidence was higher in children aged between 0 to 9 years and in the elderly; there was no difference in relation to sex and the majority of cases were located in urban areas. The determination of the epidemiological profile and the the spread of disease patterns can indicate possible areas of vulnerability, in order to contribute to the management and prevention of the disease through a strategic resources optimization