Survival and development of chicken ascarid eggs in temperate pastures

Abstract

Eggs of chicken ascarids (Ascaridia galli and Heterakis spp.) are believed to be hardy and survive for long periods. However, this has not been evaluated quantitatively and our study therefore aimed to determine development and recovery of chicken ascarid eggs after burying in pasture soil. Unembryonated eggs were mixed with soil, placed in sealed nylon bags and buried at 7 cm depth in pasture plots April (spring, n = 72) and December 2014 (winter, n = 72). Eight randomly selected bags per season were used to estimate pre-burial egg recovery [0 week post-burial (wpb)]. Eight random bags were removed at 5, 12, 23, 38, 52, 71 wpb per season and additionally at 104 wpb for spring burial. The content of each bag was analysed for numbers and development stages of eggs. Eggs buried in spring were fully embryonated within 12 wpb. In contrast, eggs buried in winter were developing between 23 and 38 wpb, so that all viable eggs seemed to be fully developed by 38 wpb. About 90% eggs disappeared within 23 wpb (spring) and 38 wpb (winter). Small proportions (2-3%) of seemingly viable and infective eggs were still recovered up to 2 years after deposition. In conclusion, most eggs buried in temperate pasture soil seem to experience a heavy mortality within a few months after the deposition, especially during warm periods. However, a small proportion of eggs may survive and remain infective for at least 2 years.

Viability and development of Ascaridia galli eggs recovered in artificial media followed by storage under different conditions

“…The development of eggs was evaluated by examining egg morphology under a compound binocular microscope equipped with a digital Nikon H550S camera (Nikon Corporation, Tokyo, Japan). A minimum of 100 eggs per Eppendorf tube were examined and the proportion of eggs at different stages of development (undeveloped, early development, vermiform and embryonated) or damaged/dead were recorded for each category using the morphological classifications described elsewhere (Tarbiat et al, 2015;Thapa et al, 2017)…”

“…Ascaridia galli eggs are highly adaptable to wide ranges of environmental conditions primarily due to the inherent characteristics of their thick eggshells (Cruthers et al ., 1974; Thapa et al ., 2017). However, their long-term survival and developmental capacity are affected by several factors.…”

Prevalence of endoparasites by microscopic analysis in free-range chickens in a Brazilian semiarid region

“…The high prevalence of gastrointestinal parasites observed among the chickens of this study (62.6%), together with the high percentage of the farms that had parasitized poultry (90%), reflected errors in sanitary management on most of the farms evaluated, such as non-cleaning of facilities (p=0.05), which may have favored parasite transmission. According to Thapa et al (2017), factors such as temperature, poultry lineage and different environmental conditions can influence the development and maintenance of parasites on farms.…”

“…The semiarid region of Paraíba has a natural advantage for controlling these diseases, due to its high temperatures and low humidity, which, according to Thapa et al (2017), reduce the survival of eggs and oocysts of the parasites in the environment. Therefore, by combining this favorable condition for parasite control with correct sanitary management, through incentive programs aimed at improving facilities and correct treatment of animals, better infection control can be obtained.…”

Diurnal variation in egg excretion by Heterakis gallinarum

“…Thus, another advantage of increased egg excretion during the daytime might be associated with finding suitable micro-environments in which embryonation of the excreted eggs may be favoured. Furthermore, because ascarids eggs ( H. gallinarum + A. galli) can survive and remain infective up to 2 years when buried in soil under natural circumstances (Thapa et al , 2017), an elevated egg excretion during the active-period of the diurnal host has the potential to favour environmental contamination and a long-term survival of the eggs. A completely oppositely synchronized relationship between parasite egg release with host feces excretion and activity has been shown for Echinostoma caproni residing in mice, a nocturnal host (Platt et al , 2013).…”