Several human diseases caused by protozoa are transmitted by a variety of arthropod vectors (Table). The vectors are not simply 'flying syringes', but represent a second host for the protozoan parasite.arasites which reside within the blood or internal organs of the host have logistical problems in terms of infecting a new host. In contrast to fecal-oral transmission, where infective stages are excreted into the environment, potential new hosts would not normally come into contact with the parasite.
If you have accumulated enough work credits (typically 40) the earliest you can collect Social Security retirement benefits is 62. At that age, your monthly payment would be about 75% of the amount you would receive by waiting to retire at SSA's full retirement age. Full retirement age:
To qualify for Social Security retirement benefits, you need to earn at least 40 Social Security credits. What this means is that anyone born in 1929 or later needs to have worked at least 10 years.