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At least 19 recordsLinked to original sources

PubMed2006

Alanine transaminase levels in the year before pregnancy predict the risk of hepatitis C virus vertical transmission.

Vertical transmission is the most common route of hepatitis C virus (HCV) infection in children. Transmission risk factors have been described, but most risk factors can only be evaluated using expensive laboratory exams. The aim of the present study was to evaluate whether maternal alanine transaminase (ALT) levels before pregnancy correlate with HCV vertical transmission. Seventy-four transmitting and 403 nontransmitting mothers were evaluated. All mothers enrolled had two ALT determinations in the last year before pregnancy, at least 6 months apart. Mothers were divided into two groups: mothers with persistently normal serum ALT levels and mothers with abnormal ALT levels. In the second group both mothers with constantly raised or with fluctuating ALT levels (one normal and one raised determination) were included. ALT was defined as raised if higher than twice the upper limit of normal. Abnormal ALT levels were found in 39/74 (52.7%) HCV transmitting mothers and in 146/403 (32.6%) nontransmitting mothers (P = 0.008; relative risk 1.96; 95% confidence limits 1.19-3.23). The risk of transmission from mothers with constantly raised ALT levels was more evident than that from mothers with fluctuating ALT levels. Increased ALT levels may reflect a more severe liver disease and a higher viral load, factors known to be associated with vertical transmission. ALT determination, a simple, widely available and inexpensive test, may help in identifying mothers with an increased risk of HCV vertical transmission.

Alanine Transaminase↗

PubMed1998

Vertical transmission of human immunodeficiency virus type 1 in Japan, 1989-1997: presence of two subtypes B and E with subtype E predominance. National Cooperative Study Investigators on Vertical Transmission of HIV-1.

A collaborative group for studying vertical transmission of human immunodeficiency virus (HIV)-1 in pregnant women and their babies was established in Japan in 1989. Forty-two infants, including 13 HIV-1-infected, 25 uninfected and four of undetermined status and 15 control children born to HIV-1 negative mothers were diagnosed and followed from birth to 1.5 years. All strains from HIV-positive infants were either clade E (eight infants, 61.5%) or B (five infants, 38.5%) according to DNA sequencing specific for the HIV-1 C2-V3 region. The 42 mothers with HIV-1 were women with sexual-risk behavior from all regions, but were concentrated in the Kanto District. In this group of HIV-infected children, there was no significant difference between the transmissibility of their mother's clade E and B viruses. Eight (61.5%) of the 13 virus-infected babies were Japanese and five (62.5%) of the eight were positive for HIV-1 clade E. The V3 loop region of the clade E virus of the babies was conserved but approximately 60% of the sequences which showed a substitution of aspartic acid by asparagine at position 29. The results suggest that HIV-1 clade E may be predominant in vertical transmissions and are phenotypically different from HIV-1 in persons with various other risk behaviors in Japan.

Consensus Sequence↗

PubMed2006

Colonization and vertical transmission of Streptococcus mutans in Turkish children.

The aim of the study was to establish the colonization of Streptococcus mutans and to determine the possibility of intra-familial transmission in a group of Turkish children and their parents. A total of 56 children participated in the study together with their parents (20 fathers and 49 mothers). Saliva samples were collected from the individuals and cultivated on S. mutans selective TYCSB agar. The typical isolates of S. mutans were identified by using classical microbiological methods, as well as molecular typing of S. mutans clones which was performed by using AP PCR with OPA5 primer for the detection of transmission. The vertical transmission of salivary S. mutans was detected among 14 mother-father-child, 35 mother-child (one twins) and 6 father-child combinations. The homologies of strain types were recorded as 24% and 16.6% for mother-child and father-child combinations, respectively. A significant positive correlation (p<0.001) was found between the infected children and their parents with high S. mutans counts.

Adult↗

PubMed1997

A review of the literature on prevention of early vertical transmission of the HIV virus.

OBJECTIVE: To review the literature on early vertical transmission of the HIV virus and its possible prevention. METHOD: Databases were searched using the keywords HIV, AIDS, HIV transmission, vertical transmission, HIV pregnancy, HIV newborn, AIDS paediatric, HIV paediatric, HIV maternal, maternal immunity, HIV diagnosis. Two hundred and twenty-nine articles were generated and 41 were used in the review. FINDINGS: Factors which increase the risk of vertical transmission are: maternal drug misuse; maternal infection; malnutrition; and HIV viraemia. There are gaps in knowledge about the mechanisms and rates of transmission indicating further research is needed. KEY CONCLUSIONS: Prevention of early vertical transmission is very important; researchers need to standardise their research criteria when carrying out research so that conclusions are comparable. IMPLICATIONS FOR MIDWIFERY PRACTICE: To promote the health of women and their partners must be educated prior to conception and during pregnancy on family planning and healthy living; HIV positive women need counselling and support, and midwives must consider all unscreened pregnant women to be HIV positive.

Female↗

PubMed1997

Interactions between frequency-dependent and vertical transmission in host-parasite systems.

We investigate host-pathogen dynamics and conditions for coexistence in two models incorporating frequency-dependent horizontal transmission in conjunction with vertical transmission. The first model combines frequency-dependent and uniparental vertical transmission, while the second addresses parasites transmitted vertically via both parents. For the first model, we ask how the addition of vertical transmission changes the coexistence criteria for parasites transmitted by a frequency-dependent horizontal route, and show that vertical transmission significantly broadens the conditions for parasite invasion. Host-parasite coexistence is further affected by the form of density-dependent host regulation. Numerical analyses demonstrate that within a host population, a parasite strain with horizontal frequency-dependent transmission can be driven to extinction by a parasite strain that is additionally transmitted vertically for a wide range of parameters. Although models of asexual host populations predict that vertical transmission alone cannot maintain a parasite over time, analysis of our second model shows that vertical transmission via both male and female parents can maintain a parasite at a stable equilibrium. These results correspond with the frequent co-occurrence of vertical with sexual transmission in nature and suggest that these transmission modes can lead to host-pathogen coexistence for a wide range of systems involving hosts with high reproductive rates.

Animals↗

PubMed2004

Human herpesvirus-8 infection in pregnancy and labor: lack of evidence of vertical transmission.

To investigate whether vertical transmission of the human herpesvirus 8 (HHV-8) may occur during pregnancy or at delivery, we enrolled 295 women recruited attending the Division of Obstetrics and Gynecology of a University Teaching of Rome Tor Vergata, S. Eugenio Hospital. The study population was divided in two groups: 245 pregnant women who underwent amniocentesis for genetic screening at 16-18 weeks gestation (group 1) and 50 women at the childbirth (group 2). Maternal blood was obtained from all women. Amniotic fluid (group 1) and cord blood (group 2) were obtained at midtrimester and at delivery, respectively. The presence of anti-HHV-8 antibodies in serum samples was investigated by an immunfluorescence assay. All amniotic fluids, maternal blood, and cord blood samples from HHV-8 seropositive women were tested for the presence of HHV-8 DNA sequences by the polymerase chain reaction. Thirty women, 27 of the group 1 and three of the group 2, were found to have anti-HHV-8 antibodies. Two neonates of the three seropositive mothers of the group 2 had anti-HHV-8 antibodies in cord blood. HHV-8 DNA sequences were detected in the blood of one woman of the group 2. None of the amniotic fluid and cord blood samples had detectable HHV-8 DNA sequences. This study suggests that vertical transmission of HHV-8 is unlikely or, at least, very rare.

Adult↗

PubMed2002

[Vertical transmission of HIV in Denmark].

INTRODUCTION: Vertical transmission of HIV can be reduced if the pregnant woman and new born child receive antiretroviral treatment. Delivery by caesarean section and avoidance of breast feeding further reduce vertical transmission. The aim of this study was to describe the treatment of HIV-positive pregnant women in Denmark and the risk of vertical transmission. MATERIAL AND METHODS: We retrospectively describe the risk of vertical transmission of HIV among HIV-positive women giving birth in Denmark during the period, mid-1994 to February 2000. RESULTS: Fifty children were born. One mother gave birth twice during the study period, and one had twins. Five (10%) children were infected. All five were born by vaginal delivery. Three of the five mothers and three of the children did not receive antiretroviral treatment. The remaining two mothers were only given intrapartum treatment. In none of the five mothers was the HIV-infection known until the time of delivery or later. Transmission of HIV did not occur in the 34 mother-child pairs who received antepartum and intrapartum antiretroviral treatment, who had a caesarean delivery, who did not breast-feed, and whose children were given postpartum antiretroviral treatment. DISCUSSION: It is important to identify HIV-infection in pregnant women in order to provide the relevant treatment and prevent vertical transmission of HIV.

Anti-HIV Agents↗

PubMed1997

Maternal and viral factors in vertical transmission of HIV-1 subtype E.

Vertical transmission of HIV-1 is caused by multifactorial factors. To access the relationship of viral factors involving in perinatal transmission of HIV-1 subtype E, which is the predominant type in Thailand, plasma viral load, blood CD4+ lymphocyte level, heteroduplex mobility, and V3 sequence of the HIV-1 envelope gene were studied in 32 transmitting and 25 non-transmitting mothers. We found that HIV-1 subtype E vertical transmission was strongly associated with high maternal plasma viral RNA (> 4 x 10(4) copies/ml) and high genetic diversity of envelope gene determined by heteroduplex mobility (< 0.9). The variation of nucleotide sequences in envelope gene of subtype E vertical transmission could not determine in V3 region. Hence, plasma viral load and heteroduplex mobility can be used as prediction factors in vertical transmission of HIV-1 subtype E.

Adolescent↗

PubMed2005

Evaluation of the Sprague-Dawley rat as a model for vertical transmission of Brucella abortus.

Vertical transmission of Brucella abortus in Sprague-Dawley (SD) rats was verified with microbiologic, serologic, and polymerase chain reaction (PCR) methods. The 38 initially Brucella-free SD rats, weighing 200 to 250 g, were injected subcutaneously with 50 microL of a suspension containing 1 x 10(9) colony-forming units (cfu) of B. abortus biotype 1 Korean isolate. The rats were allowed to mate with uninfected SD rats. The isolate was detected by culture and by AMOS (abortus, melitensis, ovis, suis) PCR in testis tissue of infected male rats and splenic tissue of infected female rats. By 7 d after inoculation, the results of both the rose bengal test (RBT) and the plate agglutination test (PAT) were positive for antibody against B. abortus; the reciprocal antibody titre ranged from 200 to 400 in the 1-mo-old offspring and 800 in their dams. The infected rats directly transmitted Brucella to their breeding partners and offspring. Fetuses of infected dams were found to be infected at 20 d of gestation. These data are discussed in relation to a model for epizootic and zoonotic cases possibly involving wild animals. Additional rigorous experiments are warranted to explore the value of this model in developing measures to prevent congenital brucellosis.

Agglutination Tests↗

PubMed1992

[Vertical transmission of HTLV-I].

Vertical transmission of the human T-cell leukemia type 1 (HTLV-1) from seropositive mothers to their offspring has been extensively studied. Transmission occurs mainly through breastfeeding. Prevention relies on screening pregnant women (and wet-nurses) for HTLV-1 antibodies and advising seropositive women to refrain breast feeding. Recently, antigen detection or genome detection (using PCR) studies on lymphocytes from neonates born to HTLV-1 positive mothers have established that prenatal vertical transmission does occur, although in only a small proportion of cases (0.5 to 7%). Studies on the HTLV-1 and improved understanding of its modes of transmission may provide new insight into the transmission of the HIV.

Cordocentesis↗

PubMedDate not supplied

Models for diseases with vertical transmission and nonlinear population dynamics.

Vertical transmission, the direct transfer of a disease from an infective parent to a new born offspring, is an important aspect of many diseases. Most of what is known for vertical transmission models assumes birth rates proportional to population size. We consider models with nonlinear population dynamics and finite carrying capacity and analyze the stability of equilibria in the special case in which the overall birth rate does not depend on infective population size.

Female↗

PubMedDate not supplied

Vertical transmission of HIV-1 infection.

Vertical transmission is the dominant mode of acquisition of infection for HIV infection in children, and about 1600 infants are newly infected each day worldwide. Without interventions the risk of transmission is between 15% and 35%, and associated with maternal disease progression, prematurity, duration of rupture of membranes, length of labour, and vaginal delivery. Breastfeeding approximately doubles the risk of vertical transmission; the additional risk of transmission through breastfeeding is approximately 15-20%, with about one-third of this accounted for by late postnatal transmission after 3 months of age. Current strategies to reduce the risk of transmission include a short course of anti-retroviral therapy, avoidance of breastfeeding and Caesarean section delivery. However, even if interventions late in pregnancy or around the time of delivery are highly effective in preventing perinatal infection, it is likely that as a public health policy they are of interest only if alternatives to breastfeeding are feasible, affordable, safe and available.

Antiviral Agents↗

PubMedDate not supplied

Vertical transmission of HTLV-I/II: a review.

The vertical transmission of the human T-cell lymphotropic virus type I (HTLV-I) occurs predominantly through breast-feeding. Since some bottle-fed children born to carrier mothers still remain seropositive with a frequency that varies from 3.3% to 12.8%, an alternative pathway of vertical transmission must be considered. The prevalence rate of vertical transmission observed in Japan varied from 15% to 25% in different surveys. In Brazil there is no evaluation of this form of transmission until now. However, it is known that in Salvador, Bahia, 0.7% to 0.88% of pregnant women of low socio-economic class are HTLV-I carriers. Furthermore the occurrence of many cases of adult T-cell leukemia/lymphoma and of four cases of infective dermatitis in Salvador, diseases directly linked to the vertical transmission of HTLV-I, indicates the importance of this route of infection among us. Through prenatal screening for HTLV-I and the refraining from breast-feeding a reduction of approximately 80% of vertical transmission has been observed in Japan. We suggest that in Brazil serologic screening for HTLV-I infection must be done for selected groups in the prenatal care: pregnant women from endemic areas, Japanese immigrants or Japanese descendents, intravenous drug users (IDU) or women whose partners are IDU, Human immunodeficiency virus carriers, pregnant women with promiscuous sexual behavior and pregnant women that have received blood transfusions in areas where blood donors screening is not performed. There are in the literature few reports demonstrating the vertical transmission of HTLV-II.

Brazil↗

PubMed2000

[Application of molecular amplification methods in the diagnosis and follow-up of HIV-1 infection in children infected by vertical transmission].

BACKGROUND: To describe the vertical transmission of HIV-1 by means of molecular methods. PATIENTS AND METHODS: A prospective study between 1995 and 1998 of two groups of patients, A: 107 newborn infants to HIV-1 infected mothers, and B: 11 infants with clinical suspicion of HIV infection, born to mothers who didn't know being infected. DNA and RNA PCR as well as reverse transcriptase gen mutations were tested. RESULTS: Eleven infected patients were identified, four from group A and seven from group B. Viral load at the moment of diagnosis was higher than 100,000 copies/ml in all patients. Genotypic mutations of the studied codons were not detected in ten patients. CONCLUSION: Molecular amplification techniques are useful for early diagnosis and follow-up of HIV infection acquired by vertical transmission.

Anti-HIV Agents↗

PubMed2006

Study of vertical transmission of fowl adenoviruses.

The vertical transmission of fowl adenoviruses (FAdVs) was studied by polymerase chain reaction (PCR) and virus isolation. Liver, spleen, kidney, and bursa of Fabricius were collected from 60 chicks 1 d old representing progenies hatched to 6 broiler breeder flocks in 6 geographically different premises in Ontario, Canada. The presence of FAdV DNA sequences was detected by PCR with the use of primers specific for the conserved pVI gene of FAdV-9 in 58 (24%) of the 240 samples tested. All samples from 1 flock were negative for FAdV sequences, and only a few samples were positive in 3 flocks, whereas 32% and 72% of the samples from the other 2 flocks were positive. Testing of 1 sample with primers designed to amplify the L1 region of the hexon protein gene and amino acid sequence analysis of the PCR product indicated that the sequences were similar to serotype-8a FAdV sequences. No fowl adenoviruses were isolated in chicken hepatoma cells from any of the 30 samples inoculated. These findings imply that vertical transmission and establishment of latent infection with FAdVs can occur in chickens.

Adenoviridae Infections↗

PubMed1999

Evolution of mutualistic symbiosis without vertical transmission.

Mutualistic symbioses are considered to evolve from parasitic relationships. Vertical transmission, defined as the direct transfer of infection from a parent organism to its progeny, has been suggested as a key factor causing reduction of symbiont virulence and evolution of mutualism. On the other hand, there are several mutualistic associations without vertical transmission, such as those between plants and mycorrhizal fungi, legumes and rhizobia, and some corals and dinoflagellates. It is expected that all mutualisms evolve perfect vertical transmission if the relationship is really mutualistic, because hosts may fail to acquire symbionts if they do not transmit the symbionts by vertical transmission. We have developed a mathematical model to clarify the conditions under which mutualistic symbiosis without vertical transmission should evolve. The evolution may occur when and only when (i) vertical transmission involves some costs in the host, (ii) the symbiont suffers direct negative effects if it exploits the host too intensively, (iii) the host establishes the ability to make use of waste products from the symbiont, and (iv) the mechanism of vertical transmission is controlled by the host. We also clarify the conditions under which mutualistic symbiosis with vertical transmission evolves.

Animals↗

PubMed2006

Transmission as a predictor of ecological host specificity with a focus on vertical transmission of microsporidia.

Consideration of vertical transmission is particularly important for understanding the life cycles of entomopathogens that are naturally occurring in invertebrate populations, are a problem in beneficial insect colonies, or are under consideration as classical biological control agents. Empirical studies generally corroborate the evolutionary hypothesis that virulence should be relatively low for pathogen species that utilize vertical transmission as one mechanism for maintenance in the host population. Nevertheless, many entomopathogens with significant effects on host populations are vertically as well as horizontally transmitted. In addition to gaining a better understanding of pathogen-host interactions and population dynamics, studies of the host range and specificity of putative biological control agents can benefit by using transmission studies to better predict ecological host specificity from physiological data. Horizontal transmission requires a tightly organized host-pathogen relationship to succeed, but still involves, albeit restricted by host behavior and pathogen dosage, the physiological susceptibility of the nontarget host. Vertical transmission studies can provide increased stringency for determining the ecological host specificity of a species and may be one very accurate predictor of the ability of a pathogen to successfully host-switch when introduced into a naïve population.

Animals↗

PubMed1991

Vertical transmission of helminths: Hypobiosis and amphiparatenesis.

Vertical transmission has evolved in at least five lines of helminths and involves prenatal or, more commonly, transmammary pathways to the offspring. In this article, vertical transmission, hypobiosis and paratenesis are combined in a strategy for transmission called amphiparatenesis. Although many believe that vertical transmission of parasites is rare, Wesley Shoop suggests that it is not only significant in the evolution of certain helminths but it may have been one of the pivotal adaptations in the evolution of the eukaryotes and is essential in their continued existence.

Journal Article↗