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Baylisascaris procyonis is an intestinal nematode of raccoons ( Procyon lotor ). Within intermediate hosts, larvae can cause visceral, ocular, and neural migrans. Humans, especially children, have become infected after ingestion of larvated eggs at raccoon latrines. Eggs of B. procyonis have a thermal death point of 62 C. During 2012, we assessed the likelihood of thermal lethality on B. procyonis eggs in southern Texas. We recorded temperature every 30 min with data loggers placed on the ground in full sun and in the shade, buried 5 cm underground and the ground surface exposed to full sun or in shade, in attics with and without exhaust fans, in woodpiles, in sheds, in tree crevices, and in cars parked in the sun. Such locations represented common raccoon latrine sites or locations where B. procyonis eggs could be found. In addition, data loggers placed about 135 cm above the ground in full sun and in shade were used as controls to acquire ambient temperature. The hottest month was August (maximum 44 C), with 15 d that exceeded 38 C. However, only the car reached the lethal temperature limit, and only for 1 h. Southern Texas has one of the warmest climates in the contiguous US; however, it is unlikely that the southern Texas climate is hot enough to kill B. procyonis eggs.

The Northern Bobwhite ( Colinus virginianus ) has declined across its range. The primary cause of this decline is thought to be habitat loss and fragmentation. However, there is speculation that factors such as parasites may play a role. South Texas recently was designated a Legacy Landscape of National Significance for Northern Bobwhite Conservation and is a region with some of the highest bobwhite densities in the US. Limited studies on bobwhite parasites have been conducted in this crucial landscape. We documented helminth parasites infecting bobwhites in South Texas, identified those that are known to be pathogenic to quail, documented pathologic responses to infection, and evaluated infections related to host intrinsic and extrinsic factors. We examined 209 bobwhites and found nine species of helminths including two known to cause tissue damage in bobwhites: Tetrameres pattersoni and Oxyspirura petrowi. The cecal nematode Aulonocephalus pennula was numerically dominant and had the greatest prevalence, intensity, and abundance. Prevalence and abundance of A. pennula were significantly greater in adult than juvenile bobwhites, whereas host sex was not an important factor. Prevalence of A. pennula was significantly greater during the 2012-13 hunting season than the 2013-14 season. The abundance of A. pennula also was significantly greater in bobwhites with greater mass within each age cohort. This research provides insight regarding the factors that influence helminth infections in bobwhites from South Texas and highlights the importance of broad-scale surveys when assessing helminth infections across large regions.

The Northern Bobwhite ( Colinus virginianus ) has been steadily declining throughout much of its historic range for decades. The Rolling Plains ecoregion of Texas and western Oklahoma, historically rich with wild Northern Bobwhites and one of the last remaining quail strongholds, also has a declining population. During August and October in 2011-13, 348 Northern Bobwhites from the Rolling Plains were examined for eyeworms (Oxyspirura petrowi). Of these 348 Northern Bobwhites, 144 (41.4%) were infected with 1,018 total eyeworms. Eyeworm abundance (mean±SE) was 2.9±0.4 (range 0-64), with an intensity (mean±SE) of 7.1±0.6. Eyeworm prevalence was significantly higher in adult Northern Bobwhites (58.7%) than in juveniles (35.4%). Recent research suggests that eyeworms have the potential to cause cellular tissue damage to the eye, but it is unknown how these worms affect host survivability. This study further expands the regional distribution of O. petrowi in Northern Bobwhites in the Rolling Plains ecoregion and assesses the prevalence and abundance of infection across host age, host sex, and year. Further research is warranted on the life history of O. petrowi and assessing the impacts of eyeworms on their definitive host at individual and population levels.

We collected 180 Blue-winged Teal ( Anas discors ) in September and October 2002 from Florida, US (n=100, representing the eastern migratory corridor) and the Louisiana-Texas, US, border (n=80, representing the western migratory corridor) and examined for blood parasites using thin heart-blood smears. Leucocytozoon simondi, Haemoproteus nettionis, and microfilariae were found in 16, 23, and 27 birds, respectively. Prevalence of L. simondi and H. nettionis did not vary by migratory corridor, but the prevalence of microfilariae was higher in the western corridor (23%) than the eastern corridor (9%). No differences in prevalence of L. simondi, H. nettionis, and microfilariae were observed by host age or sex. The mean density of L. simondi and H. nettionis averaged 1.5±0.3 and 2.3±0.4 (±SE per 3,000 erythrocytes), respectively. Ranked abundance models for main and interactive effects of corridor, age, and sex were not statistically significant for L. simondi or H. nettionis. Low prevalence and abundance of hematozoa in early autumn migrants reflects the likelihood of low exposure probabilities of Blue-winged Teal on the breeding grounds, compared to their congeners.

Historically, lead poisoning through lead shot ingestion was one of the largest health issues affecting waterfowl in North America. Lead shot was banned for use in waterfowl hunting in the US in 1991 and was banned in Canada in 1997. However, biologists need to understand how, and if, lead shot remaining in the environment will continue to impact waterfowl. Our goal was to estimate lead and nontoxic shot consumption by female Northern Pintails (Anas acuta) wintering along the Texas coast. We found shot or metal fragments (or both) in the gizzards of 39 (17%) of 227 female Northern Pintails collected along the Texas coast. Of these, lead shot was found in seven gizzards, steel shot was found in 24 gizzards, and other metal and fragments were found in 20 gizzards. Some females consumed multiple shot types. Overall, shot (lead and nontoxic combined) ingestion rates were similar to those found prior to the lead shot ban in Texas (14%) and Louisiana (17%); however, lead shot ingestion rates were considerably lower, suggesting that it is becoming less available over time. All Northern Pintails that had lead shot in their gizzards were collected from coastal habitats. While it seems that lead shot ingestion by Northern Pintails has decreased since the ban was put in place, monitoring lead shot ingestion rates from different regions will provide insight into its availability in different habitats and under various environmental conditions.

We captured 36 Northern Bobwhites (Colinus virginianus) in Mitchell County, Texas in June-September 2013, and examined them for the eyeworm Oxyspirura petrowi. We recovered 334 eyeworms from 28 of 29 adult bobwhites (97%); infections ranged from 1-40 worms and mean (± SD) abundance of 11.9 ± 13.0. Three of seven juveniles were infected, and those infected had one eyeworm each. Prevalence of eyeworms was similar among months. However, mean abundance of eyeworms peaked in July and August (3.3 ± 2.1, 13.5 ± 15.0, and 16.9 ± 15.5), and decreased in September (6.3 ± 3.0). We suggest that several previous studies may underreport prevalence and abundance because in those studies only the eye surface and nictitating membrane were examined, and not eye-associated tissue, ducts, glands, or sinuses.

Background: Oxyspirura petrowi appears to be emerging as a nematode parasite that could negatively impact Northern Bobwhite quail individuals and populations within Texas and other regions of the United States. Despite this eye worm's potential importance in the conservation of wild quail, little is known about the general biology and genome composition of O. petrowi. To fill the knowledge gap, we performed a small scale random genome sequence survey, sequenced its 18S rRNA and the intergenic region between the 18S and 28S rRNA genes, studied its phylogenetic affinity, and developed a PCR protocol for the detection of this eye worm., Results: We have generated ~240 kb of genome sequence data derived from 348 clones by a random genome survey of an O. petrowi genomic library. The eye worm genome is AT-rich (i.e., 62.2% AT-content), and contains a high number of microsatellite sequences. The discovered genes encode a wide-range of proteins including hypothetical proteins, enzymes, nematode-specific proteins. Phylogenetic analysis based on 18S rRNA sequences indicate that the Spiruroidea is paraphyletic, in which Oxyspirura and its closely related species are sisters to the filarial nematodes. We have also developed a PCR protocol based on the ITS2 sequence that allows sensitive and specific detection of eye worm DNA in feces. Using this newly developed protocol, we have determined that ~28% to 33% of the fecal samples collected from Northern Bobwhites and Scaled Quail in Texas in the spring of 2013 are O. petrowi positive., Conclusions: The O. petrowi genome is rich in microsatellite sequences that may be used in future genotyping and molecular fingerprinting analysis. This eye worm is evolutionarily close to the filarial nematodes, implying that therapeutic strategies for filariasis such as Loa loa would be referential in developing treatments for the Thelazoidea parasites. Our qPCR-based survey has confirmed that O. petrowi infection is of potential concern to quail managers in Texas.

Helminth community structure (prevalence and abundance) and patterns (associations and distributions) of gizzard worms were examined in blue-winged teal (Anas discors) migrating through south Texas to their wintering grounds (n = 50) and as they migrated back to their breeding grounds (n = 50). Three species of nematodes (Amidostomum acutum, Epomidiostomum uncinatum, and Streptocara crassicauda) and 1 species of cestode (Gastrotaenia cygni) were recovered, representing 1,164 helminth individuals. Amidostomum acutum was the most prevalent (92%) and abundant (817 individuals; 70% of total worms), while G. cygni was the least prevalent (16%) and abundant (23 individuals; 2%). Ninety-eight blue-winged teal were infected with 1 to 4 species. Amidostomum acutum and E. uncinatum were the most frequently (45%) observed association of 2 or more species, followed by A. acutum, E. uncinatum, and S. crassicauda (19%), and A. acutum and S. crassicauda (14%). Significant positive correlations were mainly between A. acutum and E. uncinatum, whereas negative correlations were found between each of these 2 species and S. crassicauda. Prevalence and abundance of A. acutum and S. crassicauda were not influenced by season, host age, or host sex. However, E. uncinatum varied by season and host age. The percent similarity index indicated a relatively consistent component community pattern of high similarity irrespective of season, host age, and sex. The same helminth species were found in both fall and spring, indicating that other helminth species were not being acquired on the wintering grounds.

Aflatoxin is a widely occurring and harmful mycotoxin produced by strains of Aspergillus spp. growing on vegetable matter. We investigated the concentration of aflatoxin needed to impair normal physiologic responses and induce acute morbidity and mortality in Northern Bobwhites (Colinus virginianus). Ten wild-caught adult bobwhites (five males and five females) from southern Texas were randomly assigned to each treatment group (0, 100, 500, 1,000, and 2,000 parts per billion (ppb) aflatoxin; n=50). We orally administered 100 μL of aflatoxin, derived from Aspergillus flavus, once per week for 4 wk and monitored bird mass, daily feed consumption, liver histology, and blood chemistries. An in vitro white blood cell proliferation test was conducted using spleen tissue to determine the effect of aflatoxin on the immune system. There was no mortality in the control groups, whereas mortalities occurred in all treatment groups except in the 100 ppb aflatoxin treatment. Immunosuppression, reduction in gamma-globulin, glucose, and gamma-glutamyltransferase blood levels, and abnormal liver histology were observed in aflatoxin-exposed quail. Blood chemistry indicated cellular damage to the liver and kidneys. We concluded that short-term, acute doses of aflatoxin as low as 100 ppb can be detrimental to the health of Northern Bobwhites.

The helminth community composition and structure of 6 species of columbids residing in south Texas are reported and compared herein. Sixty individuals of the following species, rock pigeons (Columba livia [RP]), mourning doves (Zenaida macroura [MD]), Eurasian collared-doves (Streptopelia decaocto [ECD]), white-winged doves (Zenaida asiatica [WWD]), and common ground doves (Columbina passerina [CGD]), and 48 Inca doves (Columbina inca [ID]) were collected during the summer of 2006 and examined for helminths. Twelve helminth species were found (9 nematodes and 3 cestodes), representing 486 individuals. Nematodes numerically dominated the component community in all host species. Overall, helminth prevalence was similar among host sex within all dove species. However, prevalence of Skrjabinia bonini and Hymenolepis sp. in RPs was significantly different among host age groups (P = 0.01, P = 0.0002, respectively). Likewise, prevalence of Killigrewia delafondi was higher (P = 0.0001) in adult WWDs. Based on percent similarity and Jaccard's coefficient of community indices, helminth component communities were dissimilar, and the number of shared helminth species varied among host species. Data from this study suggest that the environment surrounding preferred host habitat and foraging strategies of each host species is the driving force behind helminth component communities. This study emphasizes the importance of examining co-occurring hosts at both local and regional scales to elucidate helminth community structure and patterns.

A survey of turkey vultures (Cathartes aura) in South Carolina revealed the presence of a novel haemoproteid. Haemoproteus catharti n. sp. is described from the slides developed from the blood of this vulture. The new species is a thick, halteridial form with complete margins, and is considered distinct from the other recognized haemoproteids from the diurnal raptors in shape, pigment number, parasite outline, and host-family specificity. While reviewing blood films, a series of unusual immature schizonts of Plasmodium sp. were also observed, and these are illustrated, along with another distinct haemoproteid from old slides of poor quality produced from turkey vulture blood.

The influence of spatially distinct host subpopulations on helminth community structure and pattern was examined in a migratory avian host species. Forty helminth species represented by 24,082 individuals were collected from 184 blue-winged teal (Anas discors; BWT) from 2 primary migratory corridors in Florida (eastern migratory corridor; EMC) and Louisiana and Texas (western migratory corridor; WMC). Mean species richness was greater in BWT from the WMC (x̅±SE = 10.2 ± 0.3 species) than the EMC (8.6 ± 0.2). The helminth community from the WMC had higher abundances of 6 common/intermediate species. Corridor helminth communities were similar in species composition but less similar when incorporating abundances of those species. Overlapping distributions of phylogenetically related host species that share generalist helminth species across ecologically similar habitats seem to mitigate the isolating mechanisms that are necessary for the distinct coevolutionary pathways to develop between adjacent corridors.

Wood storks (Mycteria americana) are endangered throughout their breeding range in the United States. Because of this, researchers have had little opportunity to thoroughly examine the continental wood stork population for endoparasites. The blood protozoan Haemoproteus crumenium has been identified from several populations of wood storks in North America. However, there have been no reports of wood storks being infected with species of Plasmodium or Leucocytozoon. During 2003, 42 nestling wood storks were captured at sites in Georgia and 27 free-ranging wood storks were captured at postbreeding dispersal sites in Mississippi and Louisiana. Two thin blood smears were made from each bird, and they were examined for parasites. Haemoproteus crumenium was found in 5 wood storks (7.2%), whereas Leucocytozoon sp., Plasmodium sp., and microfilariae were not observed. Mean intensity of H. crumenium was 4.4 +/- 0.7 (SE) per 2,000 erythrocytes counted. All infected wood storks were subadult or adult and were from postbreeding dispersal sites in Mississippi.

Forty-eight scaled quail (Callipepla squamata) were collected during August 2002 at Elephant Mountain Wildlife Management Area in Brewster County, Texas, and examined for helminths. Eight species of helminths were found (5 nematodes and 3 cestodes), representing 2,811 individuals. Of these species, Gongylonema sp., Procyrnea pileata, and Choanotaenia infundibulum are reported from scaled quail for the first time. Prevalence of Aulonocephalus pennula, Gongylonema sp., Oxyspirura petrowi, Physaloptera sp., P. pileata, C. infundibulum, Fuhrmannetta sp., and Rhabdometra odiosa was 98, 2, 56, 4, 60, 2, 25, and 35%, respectively. Aulonocephalus pennula numerically dominated, accounting for 88% of total worms. Statistical analyses were performed on the 5 species with > or = 25% prevalence using the after-hatch-year host sample (n = 38). Prevalence of P. pileata was higher (P = 0.049) in females than in males and higher (P = 0.037) in the sample collected from the site that had spreader dams (berms 1-2 m high and 4-55 m long constructed in varying sizes to catch and retain rainfall) than the control site (no spreader dams). Higher rank mean abundance of A. pennula and O. petrowi (P = 0.0001 and P = 0.0052, respectively) was found in the host sample collected from the site that had spreader dams than the control site. A host gender-by-collection site interaction (P = 0.0215) was observed for P. pileata. Findings indicate that scaled quail are acquiring indirect life cycle helminths in arid western Texas habitats.

The haemoproteid community of 171 eastern white-winged doves (Zenaida asiatica asiatica) from the expanding Texas population was examined using thin blood smears. During summer 1997, heart blood was taken from doves within their historical breeding range (Lower Rio Grande Valley of Texas), an intermediate region (San Antonio and surrounding area), and the new breeding periphery (north central to southeast Texas). Two species were found: Haemoproteus columbae and Haemoproteus sacharovi. Infracommunities rarely occurred in heart blood, as only 20 of 132 infected doves demonstrated gametocytes of both species. Overall prevalence of H. columbae and H. sacharovi was 77 and 15%, respectively. Prevalence of H. columbae was higher in the Lower Rio Grande Valley (LRGV) and intermediate regions than at the periphery, higher in adults than juveniles, and similar between males and females. Prevalence of H. sacharovi was lower in the LRGV than intermediate and peripheral regions, similar between juveniles and adults, and higher in females than males. Mean density of H. columbae and H. sacharovi was 15.9 +/- 2.7 and 0.3 +/- 0.1 (mean +/- SE per 3,000 erythrocytes), respectively. Overall mean abundance of H. columbae and H. sacharovi was 12.2 +/- 2.2 and 0.04 +/- 0.02, respectively. Mean abundance of H. columbae was higher in the LRGV and intermediate regions than at the periphery and was similar between host age and between host sex; H. sacharovi was similar among regions, host age, and host sex. This study emphasizes the importance of using prevalence, density, and abundance data to assess haemoproteid community structure and pattern.

Helminth communities of 171 fledged white-winged doves (Zenaida asiatica asiatica) from the expanding eastern population in Texas (USA) were examined from hosts collected 11 June to 19 September 1997 within their historical range, new breeding periphery, and an intermediate area. Eleven helminth species, representing 435 individuals, were found. Helminths occurred in three microhabitats, of which the small intestine was the most commonly occupied. Nematodes dominated numerically (76% of total worms), followed by cestodes (17%), and trematodes (7%). Infracommunities were species-poor; the most complex infracommunity consisted of three helminth species, which occurred in three host individuals, followed by two species that occurred in 13 hosts. The remaining 155 doves had one (70) or no (85) species. The overall helminth component community was species-poor and was dominated by Ascaridia columbae which occurred in 26% of the white-winged doves and accounted for 65% of all helminth individuals. Prevalence and abundance of A. columbae varied by geographic region and host age, but not by host sex. Helminth component communities varied by geographic region, host age, and host sex. These differences were primarily attributable to unique occurrences of uncommon species within specific host subpopulations. Results suggest that the white-winged doves' multimodal regional abundance pattern, sympatry with other columbids, and granivorous diet may be more important in shaping helminth community structure than the influences often associated with geographic range expansion.

Supplemental feeding of game species and the use of backyard feeders to attract avian wildlife are common practices throughout the United States. However, these activities may expose wildlife to aflatoxins. We tested the hypothesis that wild birds would avoid consuming aflatoxin-contaminated feed. Individual northern bobwhites (Colinus virginianus), white-winged doves (Zenaida asiatica), and green jays (Cyanocorax yncas) were presented with feeders that had four compartments, which contained milo that was contaminated with aflatoxin levels of 0, 100, 500, and 1,000 microg/kg, respectively. Feed remaining was weighed at 6, 12, 18, 24, 36, 48, 60, and 72 hr after the initiation of the trial. White-winged doves and northern bobwhites did not avoid contaminated feed. However, green jays selected against aflatoxin-tainted grain. Because white-winged doves and northern bobwhites did not avoid contaminated feed, the risk of exposure to this potentially hazardous toxin exists for these species.

Survival of Trichomonas gallinae was examined in white-winged dove (Zenaida asiatica) carcasses to assess whether birds that have been dead up to 8 hr can be sampled reliably for this protozoan. Carcasses of 100 T. gallinae-positive white-winged doves were separated into four groups of 25 birds, representing 2, 4, 6, and 8 hr post mortem sampling intervals and placed into an environmental chamber maintained at 27 C and 75% relative humidity. Live T. gallinae were isolated in 96, 100, 100, and 92% of the carcasses at each of the respective post mortem intervals. The experiment was repeated with another 100 carcasses of T. gallinae-positive white-winged doves placed in the environmental chamber, this time maintained at 27 C and 40% relative humidity. Live T. gallinae occurred in 96, 100, 96, and 100% of the carcasses at each of the respective post mortem intervals. Across both trials, the overall ability to detect positive birds from sampling carcasses up to 8 hrs post mortem was 97%. An a posteriori experiment was conducted in which 23 and 18 carcasses from the second trial were maintained in the environmental chamber at 27 C and 40% relative humidity and resampled at 24 and 48 hr post mortem, respectively. Live trichomonads were isolated from 91 and 44% of the carcasses at 24 and 48 hr, respectively. Results suggest live T. gallinae can be obtained from dove carcasses reliably up to 8 hr and possibly up to 24 hr after host death. The ability for T. gallinae to survive within this time interval can aid wildlife personnel in monitoring this protozoan at hunter check stations or obtaining samples from recently killed birds.

Thin blood smears of 75 wood storks (Mycteria americana) from Georgia (USA) were made during the summers of 1994-96 and examined for blood parasites. Haemoproteus crumenium was found in one of 71 juveniles and in two adults from a sample of two subadults and two adults. Intensity of infection in the juvenile and in each of the two adults was 11, 3, and 2 parasites/5,000 erythrocytes, respectively. This is the first record of H. crumenium in the wood stork from Georgia and the second published record of H. crumenium infecting this host in North America. Additionally, one juvenile was infected with a microfilarid.

The hemosporid community of 76 wild turkeys (Meleagris gallopavo silvestris) from South Carolina (USA) was examined using thin blood smears collected during January and February 1994. High prevalences and low abundances of hemosporids characterized this community. Leucocytozoon smithi and Haemoproteus meleagridis occurred in 100% and 54% of the turkeys, respectively; a Plasmodium sp. was found in one bird. Prevalence of H. meleagridis was significantly higher in juvenile turkeys than adults, but prevalences did not differ significantly among four trap sites or by host sex. Mean (+/- SE) intensities of L. smithi, H. meleagridis, and Plasmodium sp. were 3.4 +/- 0.4, 1.8 +/- 0.3, and 3.0 per 10,000 erythrocytes, respectively. Abundances of L. smithi, H. meleagridis, and Plasmodium sp. were 3.4 +/- 0.9 +/- 0.2, and < 0.1 +/- < 0.1 per 10,000 erythrocytes, respectively. Juvenile turkeys had higher rank abundance values of L. smithi than adults, whereas no differences were found among trap sites or between sexes. No differences in rank abundances of H. meleagridis were found among trap sites, host age, or host sex variables. Collectively, both common hemosporid species varied by host age, reflecting higher abundances in juvenile turkeys. patterns of hemosporid prevalence appeared similar to patterns found in subtropical regions. Based on our data, we recommend using prevalence and abundance data to analyze the structure and pattern of hemosporid communities at the component community level.

Thin blood smears from 37 juvenile mallards (Anas platyrhynchos) collected in the Playa Lakes Region of Texas during summers 1990 and 1991 were examined for hemosporids. Only one bird was infected with a Plasmodium sp. Parasite intensity was seven per 10,000 erthrocytes. The low prevalence of Plasmodium sp. and the lack of other blood parasites in resident mallards suggests that hemosporid parasitism at the southern periphery of their breeding range is very different from that at the northern breeding grounds.

Two hundred thirty-one mallards (Anas platyrhynchos) collected during 1989-91 on the Southern High Plains of Texas were examined for macroscopically detectable Sarcocystis spp. Only eight adult mallards were infected. Based on small quantified tissue samples, five, one, and two birds had light, medium, and heavy infections, respectively. Prevalences were 4%, 8%, 9%, and 0% across two consecutive summer and winter periods, respectively. A new locality record for Sarcocystis spp. was established in both migratory and breeding populations of mallards. Our data suggest that geographic regions other than the Southern High Plains are more important in the transmission of Sarcocystis spp. in mallards.

Two species of hematozoa, Haemoproteus columbae and H. sacharovi, were observed on thin blood smears from populations of mourning doves (Zenaida macroura) in the Rolling Plains (RP, a semiarid dryland farming and grazing area) and Southern High Plains (SHP, an intensively cultivated and irrigated agricultural region with playa lakes) of western Texas (USA). Prevalences of H. columbae and H. sacharovi were 91 and 18% in doves from the RP (n = 44 doves examined) and 81 and 36% in those from thte SHP (n = 84), respectively. Although the prevalences of these species were not significantly different between the RP and SHP, the prevalence of H. sacharovi was significantly greater in juvenile versus adult doves from both localities. Mixed infections of both haemoproteid species occurred in 11 and 24% of the doves from the RP and SHP, respectively. The frequency distributions of the relative density values (numbers of parasites/2,000 erythrocytes counted) of H. columbae and H. sacharovi were overdispersed in hosts from both localities. Relative densities of H. columbae were significantly higher in mourning doves from the RP versus the SHP; likewise those of H. sacharovi were significantly greater in juvenile versus adult doves and between localities. Observed differences in prevalence and relative density of the two species in the haemoproteid community across spatial and host variables may reflect differences in vector transmission and in the physiological and immunological status of the host. This study emphasizes the importance of using adequately quantified density data versus only prevalence data when examining microparasite communities at the component community level.

Ten thin blood smears from mourning doves (Zenaida macroura) infected with Haemoproteus maccallumi were examined by each of two observers using identical techniques and microscopy in an attempt to delineate the factors necessary to provide an accurate estimate of the number of parasites/n erythrocytes. The number of erythrocytes examined must be actually counted, not estimated from extrapolated partial counts or from the number of fields of view examined. Doubling the number of erythrocytes counted (1) decreased the overdispersed frequency distribution patterns in only 25% of the replicate counts for numbers of H. maccallumi/100 erythrocytes for a series of 2,000 versus 4,000 erythrocytes counted; and (2) did not significantly increase the accuracy for determining parasite intensities. Thus, the number of erythrocytes that must be counted to determine parasite intensities could be considerably reduced from the 10,000 or 20,000 estimated for most studies, and still provide an accurate determination of the number of parasites/n erythrocytes in datasets collected from hosts with moderate to high levels of parasitemia. This resulted in a decreased amount of time expended by the observer on each blood smear examined. With two equivalently trained individuals, differences between observers examining the same blood smears were minimal. This study suggests an approach by which a more standardized methodology for quantifying blood parasite intensities could be developed.