Diseases can be transmitted directly and indirectly. Vertical transmission of disease is one of the important modes of direct transmission of disease. Vertical means the movement from plane above to plane below and horizontal means movement who reside in the same plane. A child is born through mother. So the mother resides in plane above and the child in the plane below. We others reside in the same plane.
Diseases of vertical transmission are the diseases which a child gets from his/her mother during intrauterine life, during birth and during infancy and young childhood. The diseases are transmitted through placenta during intrauterine life, through passage of birth canal during delivery procedure and through breast feeding of lactating mother.
The important infections acquired through placenta are toxoplasmosis caused by Toxoplasma gondii, congenital rubella syndrome caused by German measles, cytomegalic inclusion disease caused by Cytomegalovirus, hepatitis caused by Hepatitis B virus, AIDS caused by HIV virus and congenital syphilis caused by Treponema pallidum. They cause intrauterine growth retardation and several congenital anomalies.
For toxoplasmosis explaining the mechanism of transmission can help mothers to be careful during pregnancy. Cats get tissue cysts by ingestion of tissue cysts present in flesh of birds and rats. Cats defecate. Fecal oocysts go to rats and birds and found in their tissue as tissue cysts. Fecal oocysts contaminate vegetables & fruits. Vegetarian animals like pig, sheep, goat and cow gets the disease. Human being consumes vegetables, fruits, milk, milk products and meat and gets the disease. Human being can also get the disease by blood transfusion.
The most important and dangerous is transplacental transmission. So a pregnant mother should always wash hand before cutting vegetables, fruits, should wash them properly, eat boiled egg, boiled milk, cook meat well and should not handle or caress cats.
Infants born to mothers who had suffering from rubella particularly in the first trimester of pregnancy may suffer from multiple congenital defects. This condition is called the congenital rubella syndrome. For prevention MR vaccine is given to every child at 9 months and repeated at 15 months age. So that the girls when will arrive in child bearing age will not get the disease so that they will not transmit the diseases to their offspring and thus devastating congenital rubella syndrome can be prevented.
Cytomegalovirus is a viral disease. Transmission sources of CMV include saliva, breast-milk, cervical and vaginal secretions, urine, semen, tears, blood products and organ allographs. The spread of CMV requires very close or intimate contact. Transmission occurs by direct person-to-person contact but indirect transmission is possible via contaminated fomites. The most important and dangerous transmission is transmission to the fetus from mother through placenta. CMV occasionally causes the syndrome of cytomegalic inclusion disease (hepatosplenomegaly, jaundice, petechia, purpura and microcephaly in neonates.
Ways of Prevention: Pregnant women can take steps to reduce their risk of exposure to CMV and so reduce the risk of CMV infection of their fetus.. To avoid exposure to children's bodily fluids that might contain CMV: Pregnant woman should wash your hands often with soap and water for 15-20 seconds, especially after changing diapers,, feeding a young child, wiping a young child's nose or drool, handling children's toys. Pregnant woman should not share food, drinks, or eating utensils used by young children, should not share a toothbrush with a young child, should avoid contact with saliva when kissing a child and should not put a child's pacifier in her mouth.
Blood transfusion should take special precaution for high risk patients. A foster mother needs to be arranged for the child for breast feeding and care by the foster mother. Hepatitis B virus is present in high concentrations in blood, serum and serous exudates and in moderate concentrations in saliva, vaginal fluid and semen. Children get the disease through blood transfusion, injection, vaccination commonly and may get the disease occasionally if sexually abused by a person who bears the hepatitis B virus. Transplacental passage may affect the fetus causing neonatal hepatitis. In Bangladesh Hepatitis B vaccine is incorporated in pentavalent conjugate vaccine. The third dose here is 1 month interval from 2nd dose.
So the gap of 6 months from 2nd dose to 3rd dose is missing. This needs careful thought. Blood should be screened before transfusion. Unnecessary IV fluids and IV injections should be avoided. Children should be protected against sexual abuse and sexual adventure.
The primary route of infection of AIDS in the pediatric population is vertical transmission. Vertical transmission can occur before (intrauterine through placenta), during (intrapartum) or after delivery (through breast feeding).
According to conservative estimates pediatric AIDS form 2% of all AIDS cases in the West. In the developing world, pediatric AIDS comprises 15 to 20% of all cases. Unless preventive measures are taken on war-foot, it may wipe out the benefits brought about by the modern medicine in the foreseeable future. Risk factors for Pediatric AIDS include:
Mothers who are addicted to intravenous drugs, mothers who indulge in prostitution, mothers who are heterosexual with bisexual husbands, a history of blood transfusion with blood or its products including factor VIII concentrate within the preceding 5 years, a history of residence of certain geographical areas that are inhabited considerably with AIDS patients.
For prevention of Pediatric AIDS blood should be screened before transfusion. Unnecessary IV fluids and IV injections should be avoided. Children should be protected against sexual abuse and sexual adventure. A foster mother needs to be arranged for the child for breast feeding
Congenital syphilis: Maternal syphilis may cross the placenta and cause infection to the fetus, the risk being almost 100%. The infection may cause stillbirth or hydrops fetalis. Early manifestations include skin lesions (bullous, maculopapular or condylomatous over palms and soles, rhinitis or snuffles (frequently blood stained discharge), jaundice, hepatosplenomegaly, generalized lymphadenopathy, Coombs negative hemolytic anemia, thrombocytopenic purpura, bony lesion (osteitis, osteochondritis), pseudoparalysis usually unilateral often upper limbs), perioral and perianal ulcerations. Intrauterine growth retardation is invariably present.
Head may be microcephalic or hydrocephalic. Late manifestations seen after age of 2 years includes interstitial keratitis, frontal bossing, saber shins and tooth changes. Early diagnosis and treatment of congenital syphilis is part of prevention. Early diagnosis and treatment of syphilis of parents can prevent this catastrophic outcome.
The important infections acquired through passage of birth canal are Group B Streptococcus, Gonococcus, Chlamydia trachomatis, Herpes genitalis, Candida albicans and Trichomonas vaginalis. Group B Streptococcus causes neonatal sepsis, gonococcus causes ophthalmia neonatorum, Chlamydia trachomatis causes neonatal conjunctivitis, herpes genitalis cause herpes infection in conjuncitive, skin and mucosa, Candida albicans is a common cause of oral mucous membrane infection (thrush) and perineal skin infection (candida diaper dermatitis) in 2-5% of normal newborns. Untreated trichomoniasis of a pregnant mother is a risk factor for premature delivery of baby causing low birth-weight. Early diagnosis and treatment of reproductive tract infection is important. During delivery cleanliness is the most important step. Here cleanliness means cleanliness of the carrying woman, cleanliness of the bed where she will deliver, cleanliness of the hand of the health care provider who will conduct delivery and cleanliness of the instruments of delivery.
The important diseases transmitted through breast milk are HIV/AIDS and cytomegalovirus. Foster mother needs to be arranged for taking care of the child whose mother has the diseases which can be transmitted through breast milk. Pulmonary tuberculosis is not transmitted through breast milk. But the infant will be in such a close proximity that he/she will get it through droplet infection. So the mother must be treated before bringing the infant in close proximity.
Chickenpox is also not transmitted through breast milk but the infant gets the disease by direct contact. So the mother should not breast feed the child up to seven days after the appearance of rash. For tuberculosis and chickenpox foster mother needs to be arranged. Galactosemia and phenylketonuria are inborn errors of metabolism having genetic origin. The diseases are not transmitted through breast milk. However these children cannot be breastfed neither from her mother nor from foster mother. Appropriate infant formula milks are needed.
Dr. Md. Tufael Hossain
Assistant Professor
Community Medicine, CBMCB