PIP: It is generally believed that extended families encourage high fertility, but a review of the theoretical discussions and empirical research examining the relationship between family type and fertility fails to show any support for the customary belief. Nuclear families consist of husband, wife, and their immediate children. The extended family is broadly defined as any group of related persons living together which includes but is larger than the nuclear family. The main theoretical discussions of extended family and fertility are by Davis (1957); Davis and Blake (1956); Lorimer (1954); and Goode (1963; 1964). In the patrilocal extended family, the wife wants to have offspring as early as possible to strengthen the family line and her own status in the household. In a truly joint household the authority of the elders continues after marriage; the reproductive behavior of a couple is subject to their influence. Less intimate or less intense interspousal communication precludes the possibility of discussion on fertility-related problems and family planning. Younger age at marriage and lack of privacy contributes to higher fertility. According to Goode extended family behavior is characterized by more rules for behavior, while nuclear families emphasize the conjugal bond. Since most affinal and consanguineal kin are excluded from day-to-day decisions in the nuclear family there are weaker reciprocal controls.
Genotype VI-paramyxovirus (GVI-PMV1) is a major cause of epidemic Newcastle-like disease in Columbiformes. This genotype of avian paramyxovirus type 1 has diversified rapidly since its introduction into the US in 1982 resulting in two extant lineages, which have different population growth properties. Although some GVI-PMV1s replicate poorly in chickens, it is possible that variants with different replicative or pathogenic potential in chickens exist among the genetically-diverse GVI-PMV1s strains. To determine if variants of Columbiform GVI-PMV1 with different phylogenetic affiliations have distinct phenotypic properties in chickens, we investigated the replicative properties of 10 naturally circulating pigeon-derived isolates representing four subgroups of GVI-PMV1 in primary chicken lung epithelial cells and in chicken embryos. Our data demonstrate that GVI-PMV1 variants have different infection phenotypes in their chicken source host and that properties reflect subgroup affiliation. These subgroup replicative properties are consistent with observed dynamics of viral population growth.