Endoparasites of black-bellied whistling ducks in southern Texas.

Endoparasites detected in the black-bellied whistling duck (Dendrocygnaautumnalis) include one nasal mite, four nematodes, three trematodes, five cestodes, and two acanthocephalans. Each of these represents a new host record. Overall, 47% of the birds were parasitized with an average of 12 helminths per infected bird. Helminths were significantly more common in juveniles than in adults; more females than males were parasitized, but the difference was not statistically significant. No correlation existed between the parasite load and the physical condition of the host. Tissue damage in infected birds was minimal and limited to nematode cysts in the proventriculi. Parasite loads were light, apparently reflecting the food habits of the host.     

Peracute sodium toxicity in free-ranging black-bellied whistling duck ducklings

From 23 to 25 July 2002, 98-103 newly hatched black-bellied whistling ducks (Dendrocygna autumnalis) were observed alive at an inland saline lake (La Sal Vieja) in Willacy County, Texas (USA). Seventy-one (71%) died after showing signs indicative of sodium toxicity within 5 hr of entering the water; some died within minutes. Six carcasses were sent to the United States Geological Survey, National Wildlife Health Center (Madison, Wisconsin, USA) for analysis, and brain sodium levels of all ducklings were above 2,000 parts per million wet weight. More black-bellied whistling duck ducklings are likely to have been affected, but they were not observed after hatching.     

Experimental inoculation of mallard ducks (Anas platyrhynchos platyrhynchos) with Borrelia burgdorferi

Birds have been incriminated as disseminaters of Borrelia burgdorferi and have the potential to spread the organism over a wide geographic range. Borrelia burgdorferi has been isolated from the liver and blood of passerine birds and from Ixodes dammini removed from passerines. The objective of this study was to determine if waterfowl, specifically mallards (Anas platyrhynchos platyrhynchos), were susceptible to infection with B. burgdorferi. Eight ducks were inoculated with B. burgdorferi; four orally and four intravenously (i.v.) and two ducks were inoculated with phosphate buffered saline as controls. All eight inoculated birds became infected and developed antibodies to B. burgdorferi. The spirochete was isolated from cloacal material from an orally infected duck on day 22 postinoculation (PI) and from an i.v. infected bird on day 29 PI, from the blood of an i.v. infected bird on day 7 PI, and from the kidney of an orally infected bird. Borrelia burgdorferi was detected by indirect immunofluorescence using the B. burgdorferi specific monoclonal antibody H5332 in kidneys of three orally infected birds and one i.v. infected bird and from the mesentery of one orally infected bird. These findings show that mallard ducks are susceptible to infection by B. burgdorferi and that they can be infected orally and shed the organism in the droppings. Thus, mallards could disseminate B. burgdorferi over long distances without the need of an arthropod vector.     

Experimental polyembryony in ducks]

The phenomenon of polyembryony in birds, extremely rare in natural conditions can be comparatively easily induced experimentally by cutting the blastodisk into 2 or more parts. In successful operations and optimal incubation conditions a whole embryo can develop from each physiologically isolated part. Considering experimental polyembryony from the viewpoint of the somatic embryogenesis theory, B. P. Tokin believes that "desintegration of normally correlated cell systems, tissues, organs and organism as a whole" is a necessary condition of the appearance of polyembryony in early stages of development. This work presents the results of experiments on obtaining experimental duck twins by means of physiological isolation of blastodisk portions during diapause.     

The morphology and life-cycle of Trichobilharzia arcuata n. sp. (Schistosomatidae: Bilharziellinae) a nasal schistosome of water whistle ducks (Dendrocygna arcuata) in Australia

Summary The morphology and life-cycle of Trichobilharzia arcuata n. sp. from the nasal blood vessels of Dendrocygna arcuata from northern Australia are described. T. arcuata is distinguished from all species of Trichobilharzia except T. australis and African nasal schistosomes by its location in the nasal blood vessels and by the cercariae having 16 flame cells with a formula 2[(3)+(4+1)] against 14 with a formula 2[(3)+(3+1)], or 12 with a formula 2[(3)+(2+1)] in the case of T. corvi. T. arcuata differs from the five African nasal schistosomes in the nature of the tegument, the position of the male genital papilla and the shape of the eggs and from T. australis in the position of the caecal reunion, the number of testes, the absence of spines on the ventral tegument between the ovary and the seminal receptacle, the shape of the eggs and the presence of two germinal masses in the miracidium. Lymnaea lessoni exposed to miracidia of T. arcuata developed patent infection in 22 to 41 days. Intramolluscan development of T. arcuata is similar to T. stagnicolae and T. physellae. Domestic Muscovy ducks and pigeons developed patent infections in 22 and 12 days respectively. Chickens, a black duck and a grey teal did not become infected. ac]19840616     

Correlates of lifetime reproductive success in three species of European ducks

Number of breeding attempts is a strong correlate of lifetime reproductive success (LRS) in birds, but the relative importance of potentially interacting factors affecting LRS has rarely been fully evaluated. We considered simultaneously five main factors hypothesized to influence LRS (age at first breeding, nesting date, number of breeding attempts, female traits, brood parasitism) by analyzing with path analysis 22-year data sets for 1,279 individually marked females and their offspring in tufted duck (Aythya fuligula), common pochard (A. ferina) and northern shoveler (Anas clypeata). We recaptured marked offspring as breeding adults (n=496 females) and obtained more complete estimates of LRS by incorporating information about banded ducklings of both sexes shot by hunters 12 months after banding (n=138). In tufted ducks and especially pochard (both diving duck species), late-hatched females tended to delay nesting until 2-years old. Most females (tufted duck, 74%; pochard, 71%; shoveler, 59%) apparently produced no breeding-age offspring. Number of breeding attempts (i.e., longevity) was the strongest correlate of LRS in all species, after controlling effects of age at first breeding, relative nest initiation date, wing length and body mass. Percentage of females producing recruits increased gradually with number of breeding attempts for all three species. Also, as expected, females nesting early in the breeding season had higher LRS than late-nesting individuals. In shoveler, female-specific characteristics of relatively longer wings and heavier late incubation body mass had positive effects on LRS, the latter feature being more common in 2-year-old nesters. In diving ducks, no relationships were detected between LRS and female-specific traits like wing length or body mass, and nor did acceptance of parasitic eggs have any deleterious impact on fitness estimates. Overall, number of fledged ducklings and LRS were related in tufted duck, weakly associated in pochard and unrelated in shoveler, implying that fledging success is not always a reliable measure of LRS.     

Hormonal and metabolic responses to overfeeding in three genotypes of ducks

Muscovy, Pekin and Mule duck are different in their body weight. To make a valid comparison in the lipid metabolism between these three genotypes, overfeeding was carried out by providing the animals with amounts of food in proportion to their body weight. Under these conditions, Muscovy ducks developed a strong liver steatosis, whereas it was not very pronounced in the Mule ducks and even less in the Pekin ducks. On the contrary, Pekin ducks showed a much marked extrahepatic fattening. At the beginning of overfeeding, there was a similarity in the three genotypes as regards the post-heparin lipoprotein-lipase (LPL) activity and the insulin and glucagon concentrations. After 10 days of overfeeding, the LPL activity dramatically fell in Muscovy and in Mule ducks, whereas it remained steady in Pekin ducks. Compared to values found at the beginning of the overfeeding period, plasma glucagon and insulin shown no evolution, except for the insulin of Pekin ducks which was dramatically higher. Those data suggest that high plasma insulin concentrations measured in Pekin ducks after 10 days of overfeeding can be responsible for the maintenance of the LPL activity, which favors the extrahepatic fattening to the detriment of liver steatosis.     

Plant growth regulator induced phytochemical and antioxidant variations in micropropagated and acclimatized Eucomis autumnalis subspecies autumnalis (Asparagaceae)

Eucomis species is a valuable plant with both medicinal and horticultural potential. The current study evaluated the role of plant growth regulator (PGR) on growth, phytochemicals, and antioxidant activity in Eucomis autumnalis subspecies autumnalis. Five cytokinins including topolins and benzyladenine (BA) at 2 µM in combination with varying (0–15 µM) concentrations of naphthalene acetic acid (NAA) were tested. In vitro regenerants were acclimatized in the greenhouse for 4 months. Highest number of shoots (9 shoots/explant) was observed with 15 µM NAA alone or when combined with BA. Acclimatized plants derived from the 15 µM NAA treatment had the highest number of roots, largest leaf area and biggest bulbs. While applied PGRs increased the iridoids and condensed tannins in the in vitro regenerants, total phenolics and flavonoids were higher in the PGR-free treatment. Among the in vitro regenerants, 5 µM NAA and 2 µM BA treatments produced the best antioxidant activity in the DPPH (55 %) and beta-carotene (88 %) test systems, respectively. A remarkable carry-over effect of the PGR was conspicuous in the phytochemical levels and antioxidant activity of the 4-month-old plants. In addition to the optimized micropropagation protocols, the current findings present a promising potential for manipulating the type and concentration of applied PGRs to improve phytochemical production and hence medicinal value in E. autumnalis subspecies autumnalis.     

Simultaneous detection of three arboviruses using a triplex RT-PCR enzyme hybridization assay

Arboviruses represent a serious problem to public health and agriculture worldwide.Fast,accurate identification of the viral agents of arbovirus-associated disease is essential for epidemiological surv...     

Experimental aerosol inoculation of Mycobacterium bovis in North American opossums (Didelphis virginiana)

The goal of this study was to evaluate the susceptibility of North American opossums (Didelphis virginiana) to aerosol inoculation of Mycobacterium bovis at two dose levels in order to gain information on disease pathogenesis, fecal shedding of the organism, and the potential role that opossums play in the spread of this disease in nature. Six opossums received high dose (1 x 10(7) colony forming units (cfu) by aerosol inoculation, six opossums received low dose (1 x 10(3) cfu inoculation, and six opossums were sham-inoculated with sterile water and served as controls. Lungs were the most frequently infected tissues, with nine of 12 inoculated opossums positive for M. bovis on culture. Gross lesions consisted of multifocal pneumonia and enlarged lymph nodes. Microscopically, granulomatous pneumonia and granulomatous lymphadenitis associated with acid-fast bacilli were present in eight of 12 inoculated opossums. Fecal shedding of M. bovis was uncommon at both inoculation doses. While opossums were highly susceptible to aerosol inoculation of M. bovis, they did not become emaciated or develop widely disseminated lesions. From this study, opossums may transmit tuberculosis by aerosol infection to other opossums in close contact and serve as a source of infection to carnivores that feed upon them, however, transmission of the disease to large herbivores by fecal shedding or direct contact may be less likely.     

Experimental inoculation of North American opossums (Didelphis virginiana) with Mycobacterium bovis

Eight North American opossums (Didelphis virginiana) were inoculated with 1 x 10(5) colony forming units of Mycobacterium bovis to investigate their potential as reservoir hosts for bovine tuberculosis in Michigan. Four animals received this dose orally and four were inoculated intramuscularly (i.m.). In each group, two animals were euthanized 1 mo postinoculation (PI) and two at 2 mo PI. Four control animals were housed separately and sacrificed in the same manner as those inoculated. One of four orally inoculated opossums and three of four i.m.-inoculated opossums were positive for M. bovis by culture of tissues obtained at necropsy. The oral recipient had positive cultures from intestine and pooled lymphoid samples. Pooled lymphoid samples were positive in three i.m.-inoculated animals and two of these also had positive liver and lung cultures. One animal with gross and histologic lesions compatible with tuberculosis had negative tissue cultures. The findings suggest that opossums are susceptible to M. bovis infection by multiple routes, although their relative susceptibility compared to true reservoir hosts appears to be low.     

Structure of ovaries and formation of egg envelopes in the stonefly,Leuctra autumnalis Aubert, 1948 (Plecoptera: Leuctridae). Ultrastructural studies

The investigation of ovaries and the formation of egg envelopes of the stonefly Leuctra autumnalis was carried out with light and transmission electron microscopes. The ovary of the studied species is paired and consists of several dozen panoistic ovarioles opening individually to the oviduct. The process of egg capsule formation already begins in previtellogenesis. At this time the follicular cells secrete precursors of the vitelline envelope. Analysis of the presented data suggests that the oocyte itself also takes part in the formation of the vitelline envelope during late vitellogenesis. Simultaneously, the follicular cells produce precursors of further layers of the egg capsule, i.e. two-layered chorion and extrachorion, consisting of two gelatinous layers and a flocculent one. The completely developed capsule contains channels, probably micropylar ones.     

Kinematic parameters of terrestrial locomotion in cursorial (ratites), swimming (ducks), and striding birds (quail and guinea fowl).

The importance of size, functional features and morphological features in adaptation for walking in birds were studied. The time and space kinematic parameters of locomotion were compared in two running birds, the ratites (rhea, kiwi, Paleognatiforms), in two swimming birds, (ducks) and two striding birds, (quail and Guinea fowl). The results showed that in the two phases, stance and swing, the time and space parameters worked in opposite ways: the duration of the swing was constant, but its length increased with speed. In contrast, the duration of the stance was correlated to speed, while its length was not (except in ducks). In all the birds, a higher speed was achieved by a decrease of the stance duration, and an increase of the swing length. The kinematic parameters were not used in the same way in all species: There is a size effect and large birds increase their speed mainly by increasing the frequency of their movements and the small species increase mainly their amplitude. Nevertheless, it is not the main factor and morphology, such as swimming adaptation features of the ducks, and behaviour, are important because they modify the mechanical constraints and influence the kinematics parameters.     

Parasitism of Heterotylenchus autumnalis Nickle (Nematoda: Sphaerulariidae) to the Face Fly,Musca autumnalis De Geer (Diptera: Muscidae)

New information is reported on the parasitism of Heterotylenchus autumnalis upon its principal known host, Musca autumnalis. Black to brown spots are produced on the cuticle of all infected host larvae where the nematode penetrated. The principal damage to the host is castration of the female. In laboratory tests nematode larvae were not infective and did not leave the hosts before the female fly was 1 1 days old. Nematode larvae removed from infected male flies infected other hosts, but it is believed that in nature these larvae are unable to leave the host.