31. Many of the community's natives fell victim to epidemics of new infectious diseases, to which they had no natural immunity . 32. Poorer sanitation of the time resulted in a constant exposure to the virus, which enhanced a natural immunity within the population. 33. The Lenape population had been ravaged not only by war, but by European diseases for which they had no natural immunity . 34. During the following decades, many of the natives died of diseases such as smallpox, against which they had no natural immunity . 35. As Ken Mattingly had no natural immunity to the disease, Mattingly was then replaced as Command Module Pilot by Jack Swigert. 36. Experts think it shows that very low levels of HIV can act like a vaccine that stimulates effective natural immunity , perhaps indefinitely. 37. Once bitten by a mosquito carrying the West Nile virus, a victim usually develops a natural immunity , which should last a lifetime. 38. While some plant strains may be vulnerable to one disease, for example, others may have natural immunity that enables them to survive. 39. Close contact with Europeans had brought to the villages diseases such as smallpox and tuberculosis, against which they had no natural immunity . 40. Temperate water herbivores have no natural immunity to these toxins, allowing " Caulerpa " to grow unchecked if introduced to temperate waters.
