Among animals, brucellosis is transmitted directly (contact with placenta, aborted fetus, the liquor , vaginal and/or uterus secretion) or indirectly (if infected and non-infected health herds mix while grazing or by contact with environment in which the bacteria can be found such as manure, pastures, water, etc). Most infected male animals continue to secrete Brucella via semen for the lifetime. Presence of infectious agents in udder and surrounding lymph nodes results in permanent or occasional secretion of Brucella via milk and as such it is a serious source of infection for young animals which can also be infected via uterus. In infected lambs and young goats, Brucella inhabits lymph nods of bowls and can be secreted out of their body via droppings. Infected young cattle develop the disease once they reached sexual maturity. Sheppard dogs can also spread brucellosis between ruminants but they can also get ill as well. In high humidly, low temperature and unsunny weather conditions, Brucella can survive for up to few months in water, aborted material, manure, wool, hay, on equipment or clothes. In organic materials (dirt, soil) Brucella is resistant to drying as well. Most common sources of disease in humans are contact with aborted material of infected animal via mucus, conjuctiva and damaged skin, as well as via food of undercooked dairy and meet products. Laboratory staff, butchers and people working in wool business usually get infected by breading in the infectious agent found in tissue and wool. There are reports of doctors of veterinary medicine getting infected in incidents involving blood sampling or treatment of live Brucella vaccines (syringe stabs). Transmission of brucellosis from human to human is very rare plus it can also be sexually transmitted, transmitted by bone marrow transplant, blood transfusion and from breastfeeding mother to her nursing child.