Aedes aegypti is the main vector of the virus causing Dengue fever, a disease that has increased dramatically in importance in recent decades, affecting many tropical and sub-tropical areas of the ...globe. It is known that viruses and other parasites can potentially alter vector behavior. We investigated whether infection with Dengue virus modifies the behavior of Aedes aegypti females with respect to their activity level.
We carried out intrathoracic Dengue 2 virus (DENV-2) infections in Aedes aegypti females and recorded their locomotor activity behavior. We observed an increase of up to ∼50% in the activity of infected mosquitoes compared to the uninfected controls.
Dengue infection alters mosquito locomotor activity behavior. We speculate that the higher levels of activity observed in infected Aedes aegypti females might involve the circadian clock. Further studies are needed to assess whether this behavioral change could have implications for the dynamics of Dengue virus transmission.
Zika virus (ZIKV) is an emergent threat provoking a worldwide explosive outbreak. Since January 2015, 41 countries reported autochthonous cases. In Brazil, an increase in Guillain-Barré syndrome and ...microcephaly cases was linked to ZIKV infections. A recent report describing low experimental transmission efficiency of its main putative vector, Ae. aegypti, in conjunction with apparent sexual transmission notifications, prompted the investigation of other potential sources of viral dissemination. Urine and saliva have been previously established as useful tools in ZIKV diagnosis. Here, we described the presence and isolation of infectious ZIKV particles from saliva and urine of acute phase patients in the Rio de Janeiro state, Brazil.
Nine urine and five saliva samples from nine patients from Rio de Janeiro presenting rash and other typical Zika acute phase symptoms were inoculated in Vero cell culture and submitted to specific ZIKV RNA detection and quantification through, respectively, NAT-Zika, RT-PCR and RT-qPCR. Two ZIKV isolates were achieved, one from urine and one from saliva specimens. ZIKV nucleic acid was identified by all methods in four patients. Whenever both urine and saliva samples were available from the same patient, urine viral loads were higher, corroborating the general sense that it is a better source for ZIKV molecular diagnostic. In spite of this, from the two isolated strains, each from one patient, only one derived from urine, suggesting that other factors, like the acidic nature of this fluid, might interfere with virion infectivity. The complete genome of both ZIKV isolates was obtained. Phylogenetic analysis revealed similarity with strains previously isolated during the South America outbreak.
The detection of infectious ZIKV particles in urine and saliva of patients during the acute phase may represent a critical factor in the spread of virus. The epidemiological relevance of this finding, regarding the contribution of alternative non-vectorial ZIKV transmission routes, needs further investigation.
Two hypotheses for how conditions for larval mosquitoes affect vectorial capacity make opposite predictions about the relationship of adult size and frequency of infection with vector-borne ...pathogens. Competition among larvae produces small adult females. The competition-susceptibility hypothesis postulates that small females are more susceptible to infection and predicts frequency of infection should decrease with size. The competition-longevity hypothesis postulates that small females have lower longevity and lower probability of becoming competent to transmit the pathogen and thus predicts frequency of infection should increase with size. We tested these hypotheses for Aedes aegypti in Rio de Janeiro, Brazil, during a dengue outbreak. In the laboratory, longevity increases with size, then decreases at the largest sizes. For field-collected females, generalised linear mixed model comparisons showed that a model with a linear increase of frequency of dengue with size produced the best Akaike's information criterion with a correction for small sample sizes (AICc). Consensus prediction of three competing models indicated that frequency of infection increases monotonically with female size, consistent with the competition-longevity hypothesis. Site frequency of infection was not significantly related to site mean size of females. Thus, our data indicate that uncrowded, low competition conditions for larvae produce the females that are most likely to be important vectors of dengue. More generally, ecological conditions, particularly crowding and intraspecific competition among larvae, are likely to affect vector-borne pathogen transmission in nature, in this case via effects on longevity of resulting adults. Heterogeneity among individual vectors in likelihood of infection is a generally important outcome of ecological conditions impacting vectors as larvae.
Zika virus (ZIKV) has spread in the Americas since 2015 and the potential establishment of a sylvatic transmission cycle in the continent has been hypothesized. We evaluated vector competence of five ...sylvatic Neotropical mosquito species to two ZIKV isolates. Distinct batches of Haemagogus leucoceleanus, Sabethes albiprivus, Sabethes identicus, Aedes terrens and Aedes scapularis females were respectively orally challenged and inoculated intrathoracically with ZIKV. Orally challenged mosquitoes were refractory or exhibited low infection rates. Viral dissemination was detected only in Hg. leucocelaenus, but with very low rates. Virus was not detected in saliva of any mosquito orally challenged with ZIKV, regardless of viral isolate and incubation time. When intrathoracically injected, ZIKV disseminated in high rates in Hg. leucocelaenus, Sa. identicus and Sa. albpiprivus, but low transmission was detected in these species; very low dissemination and no transmission was detected in Ae. terrens and Ae. scapularis. Together these results suggest that genetically determined tissue barriers, especially in the midgut, play a vital role in inhibiting ZIKV for transmission in the tested sylvatic mosquito species. Thus, an independent enzootic transmission cycle for ZIKV in South America is very unlikely.
Aneuploidies, such as Down syndrome (DS), are the leading cause of pregnancy loss. Abnormalities in aurora kinase proteins result in genomic instability and aneuploidy, mainly in tumors. Thus, ...polymorphisms in Aurora kinase genes could influence the occurrence of DS and spontaneous abortion. A case-control study was conducted including 124 mothers of DS children (DSM) and 219 control mothers (CM) to investigate DS risk according to
AURKA
and
AURKC
polymorphisms. Genotyping was performed using TaqMan real-time PCR. The minor allele frequency (MAF) observed in
AURKA
rs2273535 was, respectively, 0.23 in DSM and 0.20 in CM, whereas the frequency of the
AURKC
rs758099 T allele was 0.32 in case and 0.33 in control mothers. Statistical analysis showed no significant difference in the distribution of genotypes and allele frequencies between DSM and CM. According to previous history of spontaneous abortion, the
AURKA
rs2273535 genotypes (TT + AT vs. AA: OR 2.54, 95% CI 1.13–5.71,
p
= 0.02; AT vs. AA: OR 2.39, 95% CI 1.03–5.51,
p
= 0.04; T vs. A: OR 2.08, 95% CI 1.12–3.90,
p
= 0.02) and
AURKC
rs758099 (TT vs. CC: OR 4.34, 95% CI 1.03–18.02,
p
= 0.04; TT + CT vs. CC: OR 2.52, 95% CI 1.02–6.23,
p
= 0.04; T vs. C: OR 2.03, 95% CI 1.09–3.80,
p
= 0.02) were observed as risk factors for spontaneous abortion in case mothers. Our study suggests a possible relationship between
AURKA/AURKC
variants and increased risk of spontaneous abortion within Down syndrome mothers.
Down syndrome is the main genetic cause of intellectual disability. Many studies describe the clinical characteristics of DS patients; however, few have investigated the clinical profile of mothers ...who have children with DS. Advanced maternal age (≥ 35 years old) is a risk factor for DS. Although there is an overall increase in pregnancies among women with advanced maternal age, there is still a lack of awareness of the increased risk of aneuploidy. Here, we reported the clinical and epidemiological profile of DS children and their mothers in a public reference hospital in the State of Rio de Janeiro, Brazil. For data collection, we performed a face-to-face interview guided by a structured questionnaire with closed-ended questions. A total of 344 individuals, 172 mothers and their DS children, were included in this study. Our results show that 56% of the mothers sampled were ≥ 35 years of age at childbirth. Although 98% of them received prenatal care, only 4% obtained a prenatal diagnosis of DS. Most mothers reported not drinking alcohol or smoking cigarettes during pregnancy. Furthermore, 91% of women took prenatal vitamins and supplements; however, 47% were not aware of their benefits for a healthy pregnancy. Given the strict correlation between advanced maternal age and DS, prenatal care should include genetic counseling for women over 35 years of age. This study highlights the importance of prenatal care and the urgent need for better DS screening allowing for immediate postnatal care, positively impacting the life expectancy of these patients.
In Brazil dengue has been a major public health problem since DENV-1 introduction and spread in 1986. After a low or silent co-circulation, DENV-1 re-emerged in 2009 causing a major epidemic in the ...country in 2010 and 2011. In this study, the phylogeny of DENV-1 strains isolated in RJ after its first introduction in 1986 and after its emergence in 2009 and 2010 was performed in order to document possible evolutionary patterns or introductions in a re-emergent virus.
The analysis of the E gene sequences demonstrated that DENV-1 isolated during 2009/2010 still belong to genotype V (Americas/Africa) but grouping in a distinct clade (lineage II) of that represented by earlier DENV-1 (lineage I). However, strains isolated in 2011 grouped together forming another distinct clade (lineage III).
The monitoring of DENV is important to observe the spread of potentially virulent strains as well to evaluate its impact over the population during an outbreak. Whether explosive epidemics reported in Brazil caused mainly by DENV-1 was due to lineage replacement, or due the population susceptibility to this serotype which has not circulated for almost a decade or even due to the occurrence of secondary infections in a hyperendemic country, is not clear. This is the first report of multiple lineages of DENV-1 detected in Brazil.
Background:
Cellular cardiomyoplasty with bone marrow derived stromal (MSC) and mononuclear (BMNC) cells has been shown to improve performance of infarcted hearts. We performed a comparative study ...with MSC and BMNC and tested the hypothesis that captopril treatment could enhance the beneficial effect of cell therapy in large myocardial infarctions.
Methods
Male syngeneic Wistar rats underwent experimental infarction and were randomized to receive 1-3×106 MSC, 108 BMNC or vehicle (BSS group). Two additional groups were treated with captopril and received 1-3×106 MSC (Cap.MSC) or vehicle (Cap).
Results:
The ejection fraction (EF%) of MSC and BMNC-treated rats was higher than in the BSS rats, eight weeks after transplantation (33.0±4.0, 34.0±2.0 and 20.0±2.0% respectively, P<0.01). Both captopril-treated groups improved EF% similarly. But only captopril plus MSC treatment almost restored cardiac function to control levels, 8 weeks after injection (60.50±5.40% vs. 41.00±4.50% in Cap.MSC and Cap respectively, P<0.05). Many DAPI-labelled cells were found in the scar tissue of the left ventricle only in the Cap.MSC group.
Conclusions:
Cell transplantation with both MSC and BMNC produced a similar stabilisation of heart function, but the success of the cell engraftment and the recovery of cardiac performance were dependent on concomitant treatment with captopril.
In animal models the evaluation of myocardial infarct size in vivo and its relation to the actual lesion found post mortem is still a challenge. The purpose of the current study was to address if the ...conventional electrocardiogram (ECG) and/or echocardiogram (ECHO) could be used to adequately predict the size of the infarct in rats. Wistar rats were infarcted by left coronary ligation and then ECG, ECHO and histopathology were performed at 1, 7 and 28 days after surgery. Correlation between infarct size by histology and Q wave amplitude in lead L1 was only found when ECGs were performed one day post-surgery. Left ventricular diastolic and systolic dimensions correlated with infarct size by ECHO on day 7 post-infarction. On days 7 and 28 post-infarction, ejection indexes estimated by M-mode also correlated with infarct size. In summary we show that conventional ECG and ECHO methods can be used to estimate infarct size in rats. Our data suggest that the 7-day interval is actually the most accurate for estimation of infarct size by ECHO.
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