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PubMed2006

A comparative analysis of thermogenic capacity and cold tolerance in small birds.

Small birds showing marked seasonal changes in cold tolerance also exhibit winter increases in summit metabolic rate (Msum=maximum cold-induced thermogenesis or thermogenic capacity) relative to summer birds. However, some birds show modest seasonal changes in cold tolerance without winter increases in Msum and others exhibit large seasonal changes in cold tolerance with only minor changes in Msum. Thus, the degree of correlation between cold tolerance and Msum is uncertain and no interspecific study has directly addressed this question. In this study, we measured cold tolerance and Msum in summer- (21 species) and winter- (11 species) acclimatized birds from southeastern South Dakota. Msum was measured as the maximum oxygen consumption attained during exposure of individual birds to a declining series of temperatures in 79% helium/21% oxygen (helox). Cold tolerance was measured as the temperature at cold limit (TCL), which is the helox temperature that induced hypothermia in individual birds. Residuals from allometric regressions of logMsum and logTCL were significantly and negatively related for summer (R2=0.34, P=0.006) and winter (R2=0.40, P=0.037) birds. Data were also subjected to a comparative analyses with phylogenetically independent contrasts to remove potential confounding effects of phylogeny, and results were similar to the non-phylogenetic analyses, with significant negative correlations in both summer (R2=0.47, P<0.001) and winter (R2=0.40, P=0.049). Thus, birds with high Msum tended to show reduced TCL (i.e. high cold tolerance), suggesting that cold tolerance and summit metabolism are phenotypically linked in small birds.

Adaptation, Physiological↗
PubMed2005

Reservoir competence of native North American birds for the lyme disease spirochete, Borrelia burgdorfieri.

Reservoir competence for the Lyme disease spirochete, Borrelia burgdorferi, was tested for six species of native North American birds: American robin, gray catbird, brown thrasher, eastern towhee, song sparrow, and northern cardinal. Wild birds collected by mist netting on Fire Island, NY, were held in a field laboratory in cages over water and locally collected larval ticks were placed on the birds, harvested from the water after engorgement, and tested for infection by direct fluorescentantibody staining after molting to the nymphal stage. American robins were competent reservoirs, infecting 16.1% of larvae applied to wild-caught birds, compared with 0% of control ticks placed on uninfected laboratory mice. Robins that were previously infected in the laboratory by nymphal feeding infected 81.8% of applied larvae. Wild-caught song sparrows infected 4.8% of applied larvae and 21.1% when infected by nymphal feeding. Results suggest moderate levels of reservoir competence for northern cardinals, lower levels for gray catbirds, and little evidence of reservoir competence for eastern towhees or brown thrashers. Lower infection rates in larvae applied to wild-caught birds compared with birds infected in the laboratory suggest that infected birds display temporal variability in infectiousness to larval ticks. Engorged larvae drop from birds abundantly during daylight, so the abundance of these bird species in the peridomestic environment suggests that they might contribute infected ticks to lawns and gardens.

Animals↗
PubMed2002

Prevalence of Salmonella spp in selected birds captured on California dairies.

OBJECTIVE: To determine the prevalence of Salmonella spp in wild birds commonly found on California dairies. DESIGN: Prospective study. ANIMALS: 7 selected species of birds were captured on 9 dairies in Kings and Tulare counties, California. PROCEDURE: Birds were captured (using traps and nets) and euthanatized, and the entire gastrointestinal tract was removed. Contents of the gastrointestinal tract were subjected to culture for Salmonella spp. RESULTS: 892 birds were captured, and Salmonella spp were isolated from 22 birds. The prevalence by dairy ranged from 0.7 to 16.7%, whereas the prevalence by bird species ranged from 1.2 to 3.2%. Cowbirds and English sparrows had the highest prevalence of Salmonella organisms. Five serotypes of Salmonella organisms were isolated, including Meleagridis, Montevideo, Muenster, Typhimurium, and an untyped serotype. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of our findings, birds that commonly inhabit California dairies harbor Salmonella organisms. However, because of the low prevalence of Salmonella organisms in birds and the Salmonella serotypes isolated, birds are not important reservoirs of Salmonella organisms on California dairies.

Animals↗
PubMed1989

The monooxygenases of birds, reptiles and amphibians.

1. Microsomal monooxygenase systems which contain cytochrome P-450 forms as their active centres are found in birds, reptiles and amphibians. Liver provides a rich source of monooxygenases but they are also present in other tissues. 2. In the hepatic microsomes of these species, levels of cytochrome P-450 and, in most cases monooxygenase activities, are lower than are found in hepatic microsomes of mammals. 3. Amongst birds, the lowest hepatic microsomal monooxygenase activities have been reported for specialized predators (fish-eaters and raptors). 4. When birds are dosed with inducers of the 3-methylcholanthrene (MC) type, the pattern of induction is similar to that in mammals. In contrast, phenobarbitone-type inducers are less effective in birds than in mammals--in some cases having no action at all. Prochloraz is a stronger inducer in birds than in the rat; it is an inducer of mixed type in birds. 5. Partial purification of avian cytochromes P-450 indicates substantial differences in properties from those of mammals. Further differences between birds and mammals in regard to the immunochemical properties of isoforms are evident from comparative studies using Western blotting. 6. On the evidence of Western blotting and response to inducers, cytochromes of family II (P450 II) seem less well represented in birds than in mammals. 7. The low monooxygenase activities of certain species of birds may make them relatively susceptible to lipophilic environmental chemicals that are detoxified by this system.

Amphibians↗
PubMed1991

Characterization of coagulase-positive staphylococci isolated from free-living birds.

A total of 129 coagulase-positive staphylococcal strains were isolated from the nasopharyngeal region of free-living birds--81 (16%) from 501 birds of prey, 29 (25%) from 117 water birds, and 19 (2%) from 937 pheasants. Staphylococcus aureus and Staphylococcus intermedius were identified in 64 (79%) and 17 (21%) strains from birds of prey, in 1 (3%) and 28 (97%) strains from water birds, and in 4 (21%) and 15 (79%) strains from pheasants, respectively. Of the total number of the 69 S.aureus strains 45 (65%) could be biotyped. Biotype D prevailed in the strains from birds of prey. Among all the 60 S.intermedius strains 41 (68%) biotype 1 and 19 (32%) biotype 3 strains could be recognized. Biotype 1 predominated in strains from water birds and pheasants, while biotype 3 in strains from birds of prey. Resistance to antibiotics was recorded in 8 (12%) S.aureus and 5 (8%) S.intermedius strains only. Fifty-six (81%) of the 69 S.aureus strains could be typed with human phages, 30 (44%) with bovine and 41 (51%) with chicken phages. It is evident that the host range of Shimizu's (CH) phages involves not only S.aureus from chicken but also from any other birds. None of these strains was typable with canine phages. Out of the 60 S.intermedius strains 45 (75%) were lysed with Blouse and Meekins' canine phages. When human, bovine, and chicken phages were used, all the 60 strains were completely resistant.

Animals↗
PubMed1993

Spermatogenesis in birds.

It is concluded that in the birds which have been studied there is a well-defined, regular cycle of the seminiferous epithelium, and that spermatogenesis involves synchronization of the activities of germ cells within and between successive generations to produce cellular associations of the seminiferous epithelium which are essentially similar to those described in mammals. However, the area of a cellular association is smaller in birds than in most (and probably all) mammals so that numerous cellular associations are present in a cross-section of a seminiferous tubule. As in primates, in which a cellular association also covers a small area of seminiferous tubule, the wave of spermatogenesis in the Japanese quail follows a spiral path along and around a seminiferous tubule with consecutive stages of the cycle always occurring as adjacent stages along the tubule. The literature indicates that there are fewer mitotic divisions during spermatogonial proliferation in birds than has been reported for mammals and it is suggested that this difference explains the difference between birds and mammals in the area occupied by a cellular association. Work on the Japanese quail indicates that stem cell renewal and spermatogonial proliferation is simpler in the quail than has been described in some mammals. In the quail, both processes occur in the same compartment of the seminiferous epithelium and are synchronized with subsequent phases of spermatogenesis, and there does not seem to be a reserve pool of non-proliferating stem spermatogonia in the quail as has been reported for some mammals. Findings to date also indicate that spermatogenesis in birds is four times faster and produces four times the number of spermatozoa/g testis than in mammals, and that this difference is associated with a faster transit and poorer survival of spermatozoa in the male extragonadal ducts of birds than mammals. These differences between birds and mammals are interpreted as a response to selection pressure due to competition between males to inseminate partners frequently in order to provide the most viable spermatozoa at the site of fertilization when ova are ready for fertilization. In this respect, it is suggested that sperm production in birds and mammals have progressed along different lines of evolutionary development due to differences in ovulatory pattern and mating system. In particular, the high sperm production of birds is associated with the need to mate a (usually monogamous) partner numerous times a day over a period of days or weeks when a clutch of eggs is laid.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1999

The effects of reduced agent-area insecticide treatments for rangeland grasshopper (Orthoptera: Acrididae) control on bird densities.

The effects of insecticidal control programs for grasshoppers on the population density of birds were assessed under operational conditions in two rangeland sites in Wyoming during an outbreak (19 to 56 grasshoppers m(-2) on >1,500 ha). Malathion, carbaryl, and fipronil were evaluated using large-scale (>/=260 ha) reduced agent-area treatments (RAAT), in which these chemicals were applied at 50% of the standard rate (except fipronil, for which there is no standard in North America) to 80, 50, and 33% of the areas (alternating treated and untreated swaths), respectively. Grasshopper population densities were reduced by 73 to 99%, at 14 and 28 days after treatment. Significant differences among treatments within the sites were apparent, and despite disparities in the vegetation, topography, and grasshopper populations between sites, some consistent patterns of response by bird populations were found. Relative to pretreatment densities and untreated plots, at 14 days after treatment, bird densities were enhanced at one site and suppressed at the other; at 28 days after treatment bird populations were generally suppressed at both sites. However, absolute densities increased in some plots, indicating that birds still had adequate food. There appeared to be no relationship between posttreatment grasshopper and bird densities, perhaps due to the large initial insect populations. Fipronil plots generally had higher avian population densities (nongregarious insectivores and total birds) than carbaryl plots, which had bird densities greater than or equal to malathion plots. These differences were probably a function of both the toxicological properties of the compounds and the proportion of the infested land that was treated. Based on these findings, we must consider the possibility that compounds with relatively high toxicity to birds and long residual effects applied to widely spaced swaths may cause no more (or perhaps less) environmental impact than less toxic and persistent insecticides that must be applied to large proportions of infested rangeland. http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p519.html</++ +HEA

Animals↗
PubMed2005

Characterisation of avian pathogenic Escherichia coli (APEC) associated with colisepticaemia compared to faecal isolates from healthy birds.

A total of 114 avian pathogenic Escherichia coli (APEC) isolates were collected from cases of colisepticaemia occurring in broilers (77) and layers (37) within Ireland. In addition 45 strains isolated from faeces of healthy birds were included for comparison. All isolates were serogrouped, and examined for known virulence factors, mostly by PCR. The O78 serogroup represented 55 and 27% of broiler and layer colisepticaemic isolates respectively. All isolates were positive for curli fimbriae (crl, csg) and negative for afimbrial adhesin (afa). S-fimbrial (sfa) sequences were present in 8.8% of septicaemic isolates and 8.9% of healthy bird isolates. The majority of E. coli from cases of colisepticaemia (97.4%) and healthy bird (95.6%) isolates were positive for aerobactin (aer), and temperature sensitive haemagglutinin (tsh) was similarly detected in high numbers in 93.9 and 93.3%, respectively. In comparison to E. coli isolates from the faeces of healthy birds, a significantly higher percentage of isolates from septicaemic cases possessed Type 1 fimbriae (fimC) and increased serum survival (iss) gene sequences. Forty-seven (41.2%) isolates from septicaemic birds possessed P-fimbriae (pap) gene sequences, compared with only 15.6% from E. coli isolated from healthy birds. Haemolysin (hlyE) sequences were detected in 46.7% of isolates from healthy birds in comparison with 6.1% of septicaemic isolates. Sequences encoding colicin V (cvaC) were detected in 99.1% of septicaemic isolates and 82.2% of isolates from healthy birds. The K1 capsule was only present in two septicaemic isolates, both taken from layers. Motility was detected in 36.8% of E. coli isolated from cases of septicaemia, compared with 93.3% of isolates from healthy birds. These results demonstrate the presence of 11 virulence genes in E. coli isolated from cases of colisepticaemia within Ireland, and indicate the prevalence of iss and fimC.

Animals↗
PubMed2004

Serum profiles of luteinizing hormone, oestradiol and cholesterol and ovarian functions in layer poultry birds (Gallus domesticus) fed diets containing furazolidone.

This study was carried out to assess the serum profiles of luteinizing hormone (LH), oestradiol, cholesterol and ovarian functions in layer poultry birds (Rhode Island Red: Gallus domesticus) fed a diet containing various concentrations of furazolidone (FZ). A total of 40 birds were randomly assigned to receive FZ 0, 200, 400 or 800 mg/kg feed (ppm) daily during the pre-laying age, i.e. 13-18 weeks (for 5 weeks). Blood samples were collected at weekly intervals. Concentrations of LH and oestradiol in serum were estimated at alternate weeks using radioimmunoassays. Serum cholesterol levels were analysed by an enzymatic calorimetric method. Furazolidone administration was terminated at the 18th week of age. The birds were sacrificed at 22nd week of age and ovarian tissues were processed for morphometric studies. Serum LH, oestradiol and cholesterol levels were affected by age (p < 0.001) and FZ dose (p < 0.001). Serum LH and oestradiol levels were lower (p < 0.05) in birds receiving FZ 800 mg/kg feed daily compared with the controls, whereas serum cholesterol profiles were lower (p < 0.05) in all FZ-administered groups than in the control group. The mean weight of ovaries having no yolky follicles observed in the group receiving FZ 400 or 800 mg/kg feed per day was reduced (p < 0.05) compared with the control group. Dosing FZ at 800 mg/kg feed per day reduced (p < 0.05) the mean volume of ovaries having no yolky follicles compared with the control group. In birds receiving FZ 800 mg/kg feed per day, the mean length of the oviduct was reduced (p < 0.05) as compared with the control group. Morphometric studies revealed that the mean number of oocytes with diameter in the range 401-800 microm decreased (p < 0.05) in birds fed FZ 400 or 800 mg/kg feed per day. Initial egg production was affected by age (p < 0.001) and dose (p < 0.001) of FZ. The mean number of eggs laid by different groups revealed that egg production was reduced (p < 0.05) in birds receiving FZ 800 mg/kg feed per day as compared with the controls. The present data suggest that FZ causes suppression in serum profiles of LH, oestradiol, cholesterol and ovarian functions in Rhode Island Red layer poultry birds. Therefore, great care must be taken with use of FZ in layer poultry birds (Gallius domesticus) with regard to dosage and duration of administration.

Animals↗
PubMed2003

Pulsed-wave Doppler echocardiography in birds of prey.

Pulsed-wave spectral Doppler echocardiography was applied to 111 diurnal and nocturnal raptors of both sexes weighing between 190 and 4200 g. In the first stage, 40 birds were examined without special preparation; in the second stage, 15 birds were examined first when they were not anaesthetised and then when they were anaesthetised; in the third stage, 41 birds were examined after they had been fasted for different periods of time; and finally 15 birds, in which echocardiography had not been possible by using standard (dorsal) restraint and positioning, were examined after being placed in lateral and ventral recumbency. Doppler-derived diastolic inflow into the ventricles was detectable in approximately 80 per cent of the birds weighing between 190 and 2300 g independently of their weight, heart rate and whether they had been anaesthetised or fasted, and aortic blood flow was detected in about 50 per cent of them. It was possible to apply the technique under standard conditions of dorsal recumbency to only one of the birds weighing more than 3000 g and to about 80 per cent of those weighing between 190 and 2300 g. In 11 of 15 birds in which the technique could not be applied under standard conditions, blood flow could be detected in the ventricles and/or the aorta after the birds had been repositioned. No systolic blood flow through the pulmonary artery was detectable in any of the birds.

Anesthesia↗
PubMedDate not supplied

A survey of aerobic bacteria and fungi in the feces of healthy psittacine birds.

Fecal samples from 61 clinically healthy psittacine birds of a wide variety of species were cultured for bacteria and fungi. The most common bacterial isolates were gram-positive bacilli, which were recovered from 60 of the 61 birds. These organisms included Lactobacillus, Bacillus, Corynebacterium, and Streptomyces. Gram-positive cocci, cultured from the feces of 21 of the birds, included Staphylococcus epidermidis, Streptococcus spp., Aerococcus spp., and Micrococcus spp. Only 6 of the 61 psittaciformes yielded gram-negative bacteria, with Escherichia coli being the most frequent isolate. Gram-negative bacilli were recovered from 4 of the 31 privately owned birds and 2 of the 30 petshop birds sampled. In addition to the bacteria, Candida albicans, Cryptococcus laurentii, and Aspergillus sp. were isolated from 13 fecal cultures. Candida albicans was isolated exclusively from 5 petshop birds. The number of birds yielding Corynebacterium and gram-negative bacteria increased with age, whereas the number of birds yielding lactobacilli and yeasts decreased with age. The organisms isolated and their significance as potential pathogens in psittacine birds are discussed.

Animals↗
PubMed2002

The role of birds in the ecology of West Nile virus in Europe and Africa.

Surveys on wild birds conducted during the last two decades in Europe, notably Poland and the Czech Republic, to determine their infection rate with WN virus have revealed endemic foci of infection. Some species of seropositive birds were nonmigrators while others were hatchlings of migrating species. Persistently infected avian reservoirs are potential sources of viruses for mosquitoes that multiply in the temperate European zone in hot, wet summers. In the past, evidence for geographical circulation of WN viruses was based on antigenic analysis of strains from different countries while more recent epidemiological studies have relied on analysis of nucleotide sequences of the envelope gene. With the reappearance of epidemic WN fever in European countries, interest has been focused once again on the African origin of the causal agent carried by migrating wild birds. In some epidemics, isolates were made from human cases or mosquitoes and only serologic evidence for infection was available from domestic and wild bird populations. In this respect the unusual findings of anti-WN virus antibodies in a population of storks maintained in northern Germany could be interpreted as evidence for local infection. The unique susceptibility of young domestic geese in Israel in 1997-2000 to WN virus and the isolation of similar strains from migrating White storks in Israel and Egypt suggest that the recent isolates are more pathogenic for certain avain species and that migrating birds do play a crucial role in geographical spread of the virus. Knowledge of the routes taken by birds migrating between Africa and Europe will therefore help in selecting sites where attempts to isolate viruses will be most fruitful. The appearance of the disease in western European equine populations (Italy and France) requires that other birds and their migratory routes be investigated once more. It remains to be determined whether the European endemic foci of WN virus are in themselves sources of infection for other birds that migrate across Europe and do not necessarily reach sub-Saharan Africa. If this is the case it will be necessary to define the strategies for detection of virus overwintering in the European temperate climate.

Africa↗
PubMed2003

Lead and lead toxicity in domestic and free living birds.

At present, domestic and wild fauna are being exposed to aspects and factors which are foreign to the habitat in which they live. One that stands out is the enormous amount and variety of chemical compounds which, in many cases, are highly complex and which are constantly being released into the atmosphere, mainly from agricultural and industrial activity. All these substances affect some species more than others, whether they be plants or animals, from the most insignificant micro-organism to the most evolved species, among them birds. Finally, another cause of mortality in many birds is plumbism, namely death caused by the ingestion of lead. Lead has been one of the main causes of poisoning in man since ancient times due to its use in many activities although it is only recently that this toxicity has been recognized. Moreover, the use of lead pellets for shooting has resulted in the release into the environment of millions of these over many years, with serious repercussions for many bird species populations, which have ingested them either directly or indirectly. Added to this use of lead in cynegetic activities is the fate of the lead weights (sinkers or ballast) used by rod fishers, which sink to the bottom or accumulate on the banks of rivers, lakes, lagoons or reservoirs. The problem arises when these pellets or weights are ingested by birds, mainly Anatidae, which mistake them for the small stones or grit they use to triturate food in their gizzards. Small particles of lead enter the digestive tract, start dissolving in the form of lead salts, are incorporated into the bloodstream and the rest of the body, accumulate in organs like the liver or kidneys, and cause physiological or behavioural changes. When certain concentrations of lead are reached, the birds then die. If lead-poisoned birds are consumed by carrions or predators, the latter also ingest the lead so that they may also be affected or die from plumbism since, being a heavy metal, its degradation and/or elimination is very difficult. There is, therefore, no doubt that millions of birds die annually worldwide from lead poisoning (in the U.S.A., around 3,000,000), this problem being most acute in marshland. The solutions could include the introduction of legislation regulating or banning shooting, in the use of non-toxic ammunition in marshes and protected areas, the substitution of lead pellets for other non-toxic ones, such as steel, bismuth, tungsten or other suitable metals, and to go on studying other possible alternatives to end such a dramatic situation for birds all over the world.

Animals↗
PubMed2006

Prediction of equine risk of West Nile virus infection based on dead bird surveillance.

Since the introduction of West Nile Virus (WNV) to the United States in 1999, the efficacy of dead bird surveillance for the prediction of human and veterinary WNV infection has been an issue of debate. We utilized South Carolina's Department of Health and Environmental Control surveillance data from 2003 to determine whether dead bird surveillance accurately predicts equine WNV infection on a county level. We adjusted for human population density as a potential confounder of an association between WNV-positive dead bird counts and mammalian WNV risk. We found a strong positive association between avian risk of WNV death and subsequent equine mortality due to WNV in South Carolina even after adjusting for human population density. Sensitivity of dead bird surveillance as a predictor of future equine WNV risk was far superior to mosquito surveillance (95% vs. 9.5%, respectively). A Poisson regression model of the equine WNV rate as a function of WNV-positive dead bird rate, adjusting for population density and taking into account effect modification by population density shows a good fit with the data. Unlike most previous studies, we control for potential confounding of the dead, WNVpositive bird-equine WNV infection association by human population density. Yet, the positive association between dead bird surveillance and equine WNV risk remains strong and statistically significant, indicating that dead bird surveillance remains a valuable tool of WNV surveillance.

Animals↗
PubMed1996

Lyme disease spirochetes in ticks collected from birds in midwestern United States.

In a tick-spirochete survey conducted from all 1989 through fall 1992 in north-western Wisconsin, 4,256 birds (composed of 91 species) were examined for ticks. Infestations were recorded for 400 birds (composed of 30 species). Of 1,184 ticks taken from 335 birds (composed of 26 species), 60 (5%) Haemaphysalis leporispalustris (Packard) from 8 species of birds were infected with the Lyme disease spirochete. Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner. Similar surveys conducted in 1990 and 1991 in Minnesota and Michigan yielded 223 H. leporispalustris from 61 birds (composed of 23 species), all free of spirochetes. However, 1 B. burgdorferi-infected Ixodes scapularis (Say) was found on 1 bird species in Minnesota. Most ticks were collected in fall from ground-foraging birds such as thrushes and sparrows. These results confirm that tick-infested birds are important in disseminating Lyme disease spirochetes and may also play a role as sources for infecting ticks.

Animals↗
PubMed1996

Diagnostic serologic testing of cage and aviary birds for chlamydiosis and suggested confirmatory testing.

A 2 x 2 contingency table was constructed to demonstrate the relationships between detectable chlamydial antibody activity and clinical health status of tested birds. The table revealed that 65.5% of clinically ill birds were antibody positive by elementary body agglutination (EBA) (> or = 10 titers) and 59.0% were antibody positive by latex agglutination (LA). Thus, EBA was slightly more sensitive than LA in detecting antibody activity. Of the clinically normal birds, 96.7% were antibody negative (< 10 titers) by EBA and 98.3% were antibody negative by LA. Individual serum or plasma samples from a group of mixed types of psittacine birds and cockatiels were tested as a separate group, and relationships between EBA-detectable antibody activity and health status were obtained from a 2 x 2 contingency table. Sixty-six percent of birds clinically ill with signs of chlamydiosis in the mixed-type group were antibody positive, whereas only 32.3% of clinically ill cockatiels were antibody positive. Statistical analysis of the contingency table using a chi-square test demonstrated that the EBA test differentiates between individual birds on the basis of health status (P < 0.001). When testing paired serum or plasma samples by EBA, LA, and direct complement fixation (DCF), the highest percentage of significant (> or =4-fold change) titer decreases was detected by LA, and the highest percentage of significant titer increases was detected by DCF. Examples of EBA, LA, and DCF titers in paired and multiple serum or plasma samples are presented to show the variety of responses that can occur. Results reflected variations seen in individual testing of birds with titer variability seen in the first sample tested. Additional types of testing believed necessary for confirming or ruling out an infectious process in birds are outlined. The current interpretations of serologic results are given.

Agglutination Tests↗
PubMed2006

Asymptomatic infection with highly pathogenic avian influenza H5N1 in wild birds: how sound is the evidence?

BACKGROUND: Widespread deaths of wild birds from which highly pathogenic avian influenza virus H5N1 has been isolated suggest that the virus continues to be lethal to them. However, asymptomatic carriage by some wild birds could allow birds to spread the virus on migration. Confirmation of such carriage is therefore important for the design of mitigation measures for the disease in poultry. DISCUSSION: Two recent papers have reported the isolation of H5N1 from a small number of water birds in China and Russia and have concluded that wild birds can spread the viruses over long distances on migration. However, both papers contain weaknesses in the provision of ornithological and associated data that compromise conclusions that can be reached about the role of wild birds in the spread of H5N1. We describe the weaknesses of these studies and highlight the need for improved methodological description and methodology, where appropriate, and further research. SUMMARY: A rigorous assessment of whether wild birds can carry H5N1 asymptomatically is critical to evaluating the risks of spread by migratory birds on long-distance migration.

Animal Migration↗
PubMed2000

Ecology of Borrelia burgdorferi in ticks (Acari: Ixodidae), rodents, and birds in the Sierra Nevada foothills, Placer County, California.

This study examined the prevalence of Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner in host-seeking adult and nymphal Ixodes pacificus Cooley & Kohls and estimated the I. pacificus infestation and B. burgdorferi infection of rodent and avian hosts in the western Sierra Nevada foothills of northern California. Additionally, we identified species likely to participate in an enzootic cycle for B. burgdorferi in this yellow pine transition habitat. Evidence of infection with B. burgdorferi was identified in 7.3 and 5.4% of host-seeking I. pacificus adults and nymphs, respectively. Mean numbers of I. pacificus observed on rodents were 1.15 for Neotoma fuscipes Baird and 0.18 for Peromyscus spp. One of 104 ear punch tissues obtained from woodrats and none from 49 Peromyscus spp. yielded B. burgdorferi. A total of 291 collected birds representing 34 species had a mean of 0.27 I. pacificus per bird. The mean I. pacificus infestation of ground-dwelling birds was 2.5 ticks per bird. Forty-nine of 92 (53%) blood smears collected from birds were reactive to a B. burgdorferi specific antibody. This study presents the identification of a B. burgdorferi-like spirochete in birds in western North America. The tick burden and spirochete infection of birds suggests that birds may be involved in a local B. burgdorferi enzootic cycle and likely participate in the transport of ticks and spirochetes to other locations while rodents from this site do not appear to be major contributors.

Animals↗