A Nonluminescent and Highly Virulent Vibrio harveyi Strain Is Associated with “Bacterial White Tail Disease” of Litopenaeus vannamei Shrimp

Recurrent outbreaks of a disease in pond-cultured juvenile and subadult Litopenaeus vannamei shrimp in several districts in China remain an important problem in recent years. The disease was characterized by “white tail” and generally accompanied by mass mortalities. Based on data from the microscopical analyses, PCR detection and 16S rRNA sequencing, a new Vibrio harveyi strain (designated as strain HLB0905) was identified as the etiologic pathogen. The bacterial isolation and challenge tests demonstrated that the HLB0905 strain was nonluminescent but highly virulent. It could cause mass mortality in affected shrimp during a short time period with a low dose of infection. Meanwhile, the histopathological and electron microscopical analysis both showed that the HLB0905 strain could cause severe fiber cell damages and striated muscle necrosis by accumulating in the tail muscle of L. vannamei shrimp, which led the affected shrimp to exhibit white or opaque lesions in the tail. The typical sign was closely similar to that caused by infectious myonecrosis (IMN), white tail disease (WTD) or penaeid white tail disease (PWTD). To differentiate from such diseases as with a sign of “white tail” but of non-bacterial origin, the present disease was named as “bacterial white tail disease (BWTD)”. Present study revealed that, just like IMN and WTD, BWTD could also cause mass mortalities in pond-cultured shrimp. These results suggested that some bacterial strains are changing themselves from secondary to primary pathogens by enhancing their virulence in current shrimp aquaculture system

State of the Art Review: Emerging Therapies: The Use of Insulin Sensitizers in the Treatment of Adolescents with Polycystic Ovary Syndrome (PCOS)

PCOS, a heterogeneous disorder characterized by cystic ovarian morphology, androgen excess, and/or irregular periods, emerges during or shortly after puberty. Peri- and post-pubertal obesity, insulin resistance and consequent hyperinsulinemia are highly prevalent co-morbidities of PCOS and promote an ongoing state of excess androgen. Given the relationship of insulin to androgen excess, reduction of insulin secretion and/or improvement of its action at target tissues offer the possibility of improving the physical stigmata of androgen excess by correction of the reproductive dysfunction and preventing metabolic derangements from becoming entrenched. While lifestyle changes that concentrate on behavioral, dietary and exercise regimens should be considered as first line therapy for weight reduction and normalization of insulin levels in adolescents with PCOS, several therapeutic options are available and in wide use, including oral contraceptives, metformin, thiazolidenediones and spironolactone. Overwhelmingly, the data on the safety and efficacy of these medications derive from the adult PCOS literature. Despite the paucity of randomized control trials to adequately evaluate these modalities in adolescents, their use, particularly that of metformin, has gained popularity in the pediatric endocrine community. In this article, we present an overview of the use of insulin sensitizing medications in PCOS and review both the adult and (where available) adolescent literature, focusing specifically on the use of metformin in both mono- and combination therapy

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Not AvailableVibrio parahaemolyticus is an important shrimp & human pathogen and a special strain of it harbouring toxic plasmid can cause Acute Hepatopanreatic Necrosis Disease (AHPND) to shrimp. An attempt was made to isolate and further characterize this bacterium from shrimp farms of south east coast of India. From 381 shrimp farms sampled over a period of four years, 105 isolates were presumptively identified as V. parahaemolyticus. All the 105 isolates were found to be negative for PirA and PirB toxin, characteristic of AHPND V.parahaemolytiucs. The challenge experiments with representative isolates required higher number of bacteria to cause shrimp mortality. The isolates were negative for thermostable direct haemolysin (tdh), tdh related haemolysin (trh) and type III secretion system alpha and beta. The isolates were tested to be sensitive to majority of the antibiotics. This study thus indicates that V. parahaemolyticus isolates recovered from aquaculture ponds of Southeast coast of India are non-shrimp pathogenic and non-human pathogenic. Direct tissue samples (hepatopancreas and stomach) and Tryptic Soy Broth enriched bacteria population from these tissues were also found to be negative for PirA and PirB toxin, characteristic of AHPND. Based on this evidence, AHPND was not detected in any of the samples collected from these shrimp culturing areas.Not Availabl

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