Effects of starvation on survival, biomass, and lipid composition of newly hatched larvae of the blue swimmer crab, Portunus pelagicus (Linnaeus, 1758)

Lipids are crucial nutrients for survival and development of crustacean larvae. This study investigated the effects of starvation on survival, body weight, and lipid composition of newly hatched larvae of Portunus pelagicus. The results showed that during starvation, average survival time of newly hatched zoea I larvae was 3.87 days. A significant decreasing trend was detected for individual dry weight (DW) during starvation and was described as DW = 0.2x2 − 1.462x + 15.023, R2 = 0.9985, where x is the starvation duration in days. DW and total lipids decreased by 17.42 and 38.46 % after 3 days of starvation, respectively. For newly hatched larvae, total lipids were dominated by phospholipids (PL) (75.55–93.57 %) and 50.39 % of PL were utilized during the 3-day starvation period. This indicates that membrane structural lipids of newly hatched P. pelagicus larvae were oxidized as an energy source during continuous starvation. There were concurrent increases in free fatty acids and cholesterol that probably resulted from the decomposition of sterol esters to free fatty acids and cholesterol. Newly hatched P. pelagicus larvae contained substantially higher levels of 20:5n3 (18.90 %) and 22:6n3 (18.24 %) than other Portunid crabs. During starvation, the highest fatty acid reduction rates were found for 20:4n6, 20:5n3, and 22:6n3 (P < 0.05), and the preferential depletion of these fatty acids may suggest that the HUFA requirements of early P. pelagicus larvae are lower than those of the other Portunids

Prevalence of enteroviruses in healthy populations and excretion of pathogens in patients with hand, foot, and mouth disease in a highly endemic area of southwest China

Etiological carriers and the excretion of the pathogens causing hand, foot, and mouth disease (HFMD) in healthy persons, patients, and asymptomatic persons infected with HFMD as ongoing infection sources may play an important role in perpetuating and spreading epidemics of HFMD. The aims of this study were to determine the carrier status of EV-A71 and CV-A16 in healthy populations, as well as the duration of EV-A71 and CV-A16 shedding in the stools of HFMD patients in an epidemic area of southwest China. A cross-sectional study and a follow-up study were conducted in three HFMD endemic counties of Yunnan Province. Six hundred sixty-seven healthy subjects were recruited to participate in the cross-sectional study, and two stool specimens were collected from each subject. Among the healthy subjects, 90 (13.5%) tested positive for viral isolation, but neither EV-A71 nor CV-A16 was detected in healthy individuals. Of the 150 patients with probable HFMD, 55.3% (83/150) tested positive for viral isolation with presented serotypes such as EV-A71 (51.81%, 43/83), CV-A16 (32.53%, 27/83), other EVs (13.25%, 11/83), and mixed EV-A71 and CV-A16 (2.41%, 2/83). The longest duration of EV-A71 and CV-A16 shedding in stool specimens from patients with HFMD was >46 days after onset. The positive rate of EV-A71 in the stool specimens of confirmed patients dropped to 50% by the end of the third week, and the same occurred with CV-A16 by the end of approximately the seventh week after onset. Although carriers of major causative agents of HFMD in healthy populations are fewer in number, the prolonged shedding of pathogens in patients with HFMD may serve as an important factor in perpetuating and spreading HFMD epidemics