Vertical transmission

Despite the availability of an effective and safe vaccine against hepatitis B for more than two decades, HBV infection is stiU a major health problem worldwide. More than two billion individuals have been infected with HBV, and chronic infection affects approximately 350 million patients (Lavanchy 2004). While HBV infection in adults is mostly asymptomatic and self-Umiting in >80% of the cases, transmission at a younger age is associated with a high risk of chronic infection. Vertical transmission of HBV leads to chronic infection of the newborns in up to 90% of the cases. 

Wolbachia, vertical transmission, mutualistic symbiosis and reproductive parasitism... 

Yamamura, N. (1993) Vertical transmission and evolution of mutualism from parasitism. Theoretical and Population Biology 44, 95-109. 

Present scientific evidence indicates that transmission of enteric pathogens (particularly Campylobacter) is mainly horizontal, while vertical transmission from parent to progeny via the egg is considered much less likely. Studies have shown that that the majority of Salmonella and Campylobacter strains do not cause disease symptoms in poultry and that between 40% and 80% of chicken flocks are Campylobacter positive. 

Perinatal infection, or vertical transmission, is the most common cause of pediatric HIV infection. The risk of mother-to-child transmission is approximately 25% in the absence of breast-feeding or antiretroviral therapy. Breast-feeding can also transmit HIV. 

Tourette s Syndrome is a familial disorder (Pauls et ah, 1991 Walkup et ah, 1996). Twin and family studies provide evidence that genetic factors are involved in the vertical transmission within families of a vulnerability to TS and related disorders. The concordance rate for TS among monozygotic twin pairs is 50% while the concordance of dizygotic twin pairs is about 10% (Price et ah, 1985). If co-twins with chronic motor tic... 

Imase, A., Kobayashi, K., Ohmae, H., Matsuda, H. and Iwamura, Y. (2001) Horizontal and vertical transmission of mouse class 1 MHC sequence in Schistosoma mansoni. Parasitology 1 23, 1 63-1 68. 

The effect of a single NPV application can be extended by natural horizontal and vertical transmission of the pathogen within the host population. This may affect several generations of the insect after the pathogen has been introduced in the host s ecosystem. Furthermore, when adult insects are carriers of NPV, geographic spread of the disease over several miles has been observed after introduction of a virus (9). 

Sharp, K. H., Earn, 3., et al. (2007). Vertical transmission of diverse microbes in the tropical sponge Cortkium sp. Appl. Environ. Microbiol. 73, 622—629. 

Enticknap 11, Kelly M, Peraud O, Hill RT. Characterization of a culturable alphaproteobacterial symbiont common to many marine sponges and evidence for vertical transmission via sponge larvae. Appl. Environ. Microbiol. 2006 72 3724-3732. 

Zidovudine is a synthetic nucleoside analog that blocks replication of the human immunodeficiency virus (HIV) by inhibiting reverse transcriptase. The primary indication for zidovudine administration in newborns is the prevention of vertical transmission of HIV. Like chloramphenicol, zidovudine is eliminated in adults primarily by glucuronide conjugation, suggesting that newborns may have a reduced capacity to eliminate zidovudine. However, unlike... 

In sheep wdth mastitis, a chronic inflammation of the mammary gland, and concurrent scrapie, prion infection is present in FDCs and macrophages in lymphoid follicles that develop adjacent to mammary ducts (Ligios et ah, 2005). Although, there are no accounts of prion shedding from colostrum in scrapie-infected sheep without mastitis, macrophages can be shed into the milk of sheep with mastitis. Secretion of the scrapie-infected macrophages in colostrum of sheep with mastitis could potentially play a role in vertical transmission of scrapie since the route of spread from ewe to lamb has not been determined. 

Vertical transmission from mother to child is rare. Nevertheless, newborns with HBsAg-positive and HDV-... 

Fischler, B., Lindh, G., Lindgren, S., Forsgren, M., von Sydow, M., Sangfelt, R, Alaeus, A., Harland, L., Enockson, E., Nemeth, A. Vertical transmission of hepatitis C virus infection. Scand. X Infect. Dis. 

Since zidovudine seems to be relatively well tolerated both in pregnancy and in neonates, there is also much reason to consider its use during lactation in order to reduce vertical transmission of HIV. Indeed, many would regard it as highly preferable to abandoning breastfeeding by HIV-infected women. In a critical double-blind West African study the effects of a 6-month course of treatment in prenatal and lactating... 

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