Experiencing high fertility and declining mortality levels,
the developing countries are today faced with the problem of relatively
high rates of natural increase in their populations. This pace of growth
in population, influenced by high fertility levels, impedes the overall
development planning. As pointed out in a document prepared by the
Planning Commission of Pakistan, 'A vicious circle is set in motion in
which high fertility and socio-economic stagnation breed upon each
other' [5]. In the developing countries, development programmes
including birth control programmes are in operation. The sustained high
fertility levels, therefore, call for more insights into the mechanisms
operating in the society and influencing fertility. Studies of fertility
behaviour are conducted at both micro and macro levels. The difference
between micro and macro is a matter of emphasis rather than one of kind,
and both approaches are concerned with each level of social aggregation.
Macrolevel studies describe the level and pattern of change resulting
from the ongoing socio-econornic development in the society as a whole
and do not explain variations in fertility at the household level [12].
However, development programmes, which are implemented at aggregate
levels defined by geographical boundaries, influence the population in
terms of socio-economic status and fertility behaviour. There are many
factors which affect human fertility individually or collectively.
Attempts have been made to identify these factors, and conceptual
frameworks have been developed to explain the causal hypotheses. In this
context mention may be made of the demographic transition theory, which
is often applied to study fertility behaviour.
Co-occurrence of metacestodes of Echinococcus multilocularis and Taenia taeniaeformis (Cestoda) in Arvicola terrestris (Rodentia) in France
