Psittacosis and Pacheco's Disease in Psittacine Birds in Guyana

Psittacosis (also known as chlamydiosis or ornithosis) is caused by Chlamydia psittaci, an obligate intracellular parasite that infects epithelial cells of the host, multiplies and enters new cells either by contact or through the blood stream. The infective form of the organism (elementary body) is shed into the environment via faeces, ocular and nasal discharges. Signs of psittacosis in psittacines include discharges from the eyes and nose, lethargy and a greenish yellow diarrhoea. Infected birds may also be asymptomatic, and will shed organisms intermittently, for extended periods to the environment. Clinically affected birds respond to tetracycline or doxycycline therapy, and the former is often administered orally to birds in Guyana some 30-40 days before export, in accordance with import health requirements. Other birds such as turkeys, pigeons and doves are also susceptible to psittacosis. Psittacosis is transmissable to humans where flu-like symptoms accompany infection.

Megninia ginglymura feather mites from a captive piping-guan (Pipile pipile).

THE piping-guan (Pipile pipile), known locally as the ‘pawi’, belongs to the family Cracidae. This endemic bird of Trinidad is probably restricted to the dense forest in two regions of the island – Grande RiviŠre and Aripo – and its population is thought to be fewer than 200 birds (Anon 2004). The pawiis defined as a critically endangered species, largely due to excessive hunting (Temple 1998).

A practical approach to the post-mortem examination of eggs, embryos and chicks

The failure of eggs to hatch, or of young chicks to survive, is a frequent and important problem when birds are bred in captivity. Under such circumstances, the examination of eggs, embryos and 'neonates' can provide useful information. Investigative techniques that work well for poultry can be adapted to the study of samples from non-domestic birds. Meticulous dissection of specimens and cautious interpretation are essential (AU)

Retrospective and longitudinal study of salmonellosis in captive wildlife in Trinidad

Morbidity and mortality of captive wildlife at the Emperor Valley Zoo, Trinidad from 1993 to 1996 were analysed to determine involvement of Salmonella spp. A 6 mo longitudinal study was conducted to determine the frequency of isolation of Salmonella spp. from apparently healthy, sick and dead wild mammals, birds, and reptiles. The antibiograms of Salmonella isolates were determined using the disc diffusion method. Fecal samples randomly selected from animal enclosures and cloacal swabs of snakes were cultured for Salmonella spp. following enrichment in tetrathionate and selenite cystine broths. For the 1993-96 period, Salmonella spp. was implicated in 17 (12%) of 141 sick or dead animals and the predominant serotype was S. typhimurium. During the 6 mo prospective study in a mean animal population of 1,186, there were 20 (2%) and 14 (1%) animals that were sick and died respectively; Salmonella spp. was implicated in only one mortality. Overall, of 1,012 samples from apparently healthy wildlife cultured, 66 (7%) yielded 24 serotypes of Salmonella. The predominant serotype were S. seigburg (16 isolates), S. gaminara (6 isolates), and S. thompson (6 isolates). None of the samples yielded S. typhimurium. The frequency of isolation of Salmonella spp. in reptiles (14%) was significantly higher than found in either mammals (7%) or birds (3%). Sixty-five (99%) of 66 Salmonella spp. isolates exhibited resistance to one or more of the nine antimicrobial agents tested. Resistance was high to cephalothin (92%), moderate to streptomycin (35%) and tetracycline (29%), but significantly low to gentamicin (2%), chloramphenicol (0%), and sulphamethoxazole/trimethoprim (0%). The prevalence of asymptomatic infections by Salmonella spp. in zoo animals was high and the very high prevalence of antimicrobial resistance could be a problem when treating salmonellosis.

Absence of Escherichia coli 0157 in a survey of wildlife from Trinidad and Tobago

Fecal, cloacal, or rectal swabs of free-ranging and captive mammalian and avian wildlife in Trinidad and Tobago were cultured for non-sorbitol fermenting Escherichia coli and tested for 0157: H7 strains. Ability of E. coli strains to produce hemolysin and mucoid colonies also was investigated. Of 271 free-ranging mammals tested, 158 (58 percent) yielded E. coli; only one (< 1 percent) bacterial isolate was a non-sorbitol fermenter which was not agglutinated by 0157 antiserum. All isolates were negative for hemolysin production and mucoid colonial growth. Two hundred and sixty-three (90 percent) of 293 free-flying birds were positive for E. coli and all isolates were sorbitol fermenters and negative for production of hemolysin and mucoid growth. Of 175 captive wild animals from individual backyard farms and a government demonstration farm, 145 (83 percent) yielded E. coli with four (2 percent) non-sorbitol fermenters; all were negative for 0157 strains, hemolysin production, and mucoid colonial growth. Of 373 animals in a zoo, 250 (67 percent) were positive for E. coli with only two (0.5 percent) non-sorbitol fermenters. All strains were non-hemolytic and non-mucoid farms. It appears that free-ranging and captive avian and mammalian wildlife are not important reservoirs of 0157: H7 stains of E. coli in Trinidad and Tobago.(AU)

Some bacterial enteropathogens in wildlife and racing pigeons from Trinidad

Fecal and cloacal swabs or feces of wild mammalian, avian and reptilian species, either farmed or free-ranging, and of racing pigeons (Columba livia) kept in lofts were cultured for Salmonella spp., Campylobacter spp., and Yersinia spp. Of 291 free-ranging mammals tested 6 (2 percent) and 1 (< 1 percent) and 1 (< 1 percent) yielded positive culture of Salmonella spp. and Campylobacter spp., respectively. Salmonella newport was the predominant serotype isolated and the opossum (Didelphis marsupialis insularis) had the significantly highest prevalence (29 percent) of Salmonella spp. infection compared to other species such as deer (Mazama americana trinitatis), lappe (Agouti paca), tattoo (Dasypus novemcinctus), agouti (Dasyprocta leporina), and wild hog (Tayassu tajacu). Among 14 species of farmed wildlife studied, 13 (7 percent) and 10 (5 percent) of 184 fecal or cloacal samples tested were positive for Salmonella spp. and Campylobacter spp., respectively. Salmonella javians accounted for 50 percent of the Salmonella spp. isolates and C. jejuni represented 90 percent of the Campylobacter spp. cultured. Only 1 (1 percent) of 124 cloacal swabs of free-flying avian species yielded Salmonella spp. compared to 21 (17 percent) samples positive for Campylobacter spp. Of 171 racing pigeons which originated from 8 fanciers, 8 (5 percent) yielded Salmonella spp. all of which were serotype typhimurium while only 1 (1 percent) were positive for Campylobacter spp. Seven (88 percent) of 8 Salmonella spp. isolates were recovered from one fancier. Yersina spp. was not cultured from any of the above samples. Although the prevalences of Salmonella spp. and Campylobacter spp. in wildlife in Trinidad are low, the practice of wildlife farming and the increased consumption of meat from wildlife may increase the health risk to human consumers(AU)

Epidemiological investigation for arboviruses in Jamaica, West Indies

Arbovirus investigation in Jamaica was undertaken between 1960 and 1975. Serological studies showed that antibodies to dengue type virus and St. Louis encephalitis virus (SLE) were prevalent throughout the island for several years. In urban communities, the incidence of dengue antibody was higher than for SLE; however, in children under 10 years of age antibody to both viruses was rarely present. In rural areas, SLE was prevalent in adults and children. This virus was isolated from Culex nigripalpus (mosquitoes) and from a nestling Mockingbird, Mimus polyglottos, in the same rural area, during two epidemic periods, 1963 and 1968. No other group B arbovirus was encountered on the island. Group A arbovirus was virtually absent prior to the eastern equine encephalomyelitis outbreak of 1962. That virus was isolated from brain tissue of humans and equines. Two strains of Cache valley virus from mosquitoes, Anopheles grabhami, one strain from Aedes taeniorhynchus, and a strain of Wad Medani virus from a tick, Amblyomma cajenense, were also isolated (AU)

Blood parasites of some Jamaican birds

The prevalence of avian hematozoa in 1791 birds of 80 species and 22 families from Jamaica was determined. Species of Haemoproteus were the most common hematozoan encountered. Species of Leucocytozoon were diagnosed only in three over-wintering North American migrants and the genus was absent in native Jamaican birds. The low prevalence of infection (7.4 percent) of blood parasites in Jamaican birds was closely similar to that seen in Neotropical birds and far below that noted for the Nearctic avifauna of the same families. Prevalence in adult and young birds was virtually identical; transmission occurred primarily during the period February to April (AU)

A new group of viruses in Jamaica: 1. Initial studies

Sixteen isolates were uncovered from bird sera and mosquitoes collected at Caymanas Estates, Jamaica. One of these isolates was St. Louis encephalitis virus, two isolates were not fully characterised and 13 belonged to a group that was, before now, not described in Jamaica. This group had similarities to the Coxsackie A viruses but showed no serological relationship to the Coxsackie viruses to which they were most similiar. These viruses were capable of infecting man, causing at least in some cases clinical illness and possibly may be responsible for some of the fevers of unknown origin in Jamaica. (AU)

Hughes virus from Trinidadian ticks and terns

Fifteen strains of Hughes virus were isolated from Soldado Rock, Trinidad, between 1962 and 1965. Seven isolates came from ticks of the Ornithodoros capensis complex and 8 from nestling birds, Sterna fuscata.(AU)

Epidemiological investigations relating to a case of Eastern Equine Encephalitis in a Trinidadian horse

The first equine death in Trinidad known to be due to eastern equine encephalitis (EEE) is reported. Diagnosis was by serologic means only. In related epidemiologic investigations, EEE virus was not isolated from over 5,000 arthropods and the organs of 99 birds, but the serum of five of the birds had neutralizing antibodies to the virus. A strain of Wyeomyia virus and a Turlock-like virus were isolated from the mosquitoes tested (AU)

Arbovirus studies in Bush Bush Forest, Trinidad, W. I., September 1959-December 1964. IV. Vertebrate populations

An introduction has been given to the principal vertebrates of Bush Bush Forest, which include 59 species of mammal (32 of bat), 171 species of bird , 27 species of reptile, 7 species of amphibian, and an undetermined number of fish. Special attention was paid to the population dynamics, longevity, and range of small forest rodents. During the study years the populations of small rodents declined almost to the point of disappearence. (AU)

Arbovirus studies in Bush Bush Forest, Trinidad, W.I., September 1959-December 1964. II. Field program and techniques

The field program of the Trinidad Regional Virus Laboratory in Bush Bush Forest included studies in which arboviruses (their prevalence and epidemiology) were the chief interest and also studies on the biology of the arthropods and vertebrates possibly associated with arbovirus cycles. The techniques used included the exposure of sentinel animals, trapping and bleeding of small mammals and reptiles, netting and bleeding of birds, collection of bloodsucking arthropods, and observations on the diel- and seasonal-activity patterns, food sources, and habitat preferences of the more abundant species of mosquitoes.(AU)

The isolation of Cache Valley virus from mosquitoes in Jamaica

Cache valley virus has been isolated from mosquitoes on three occasions in Jamaica. Although antibodies to this virus have been encountered in man and animals, the virus has not yet been associated with clinical cases (AU)

Eastern equine encephalitis virus in the West Indies and British Guiana

Investigations on Eastern Equine Encephalitis virus in the West Indies and British Guiana are reported. In Trinidad the virus was isolated from Culex mosquitoes in 1959 and 1960. In British Guiana the virus was isolated from horses in 1959 during an outbreak of Equine Encephalitis in Rupununi Savannah. Immunity to Eastern Equine virus has been demonstrated in man, birds and domestic chickens from Trinidad. (Summary)

St. Louis encephalitis virus in Jamaican birds

Seventeen percent of 238 wild birds and 36 percent of 162 domestic birds at Caymanas, Jamaica, were found to be positive for St. Louis encephalitis virus infection by hemagglutination-inhibition and neutralization tests in 1962. Conversions detected in local and sentinel chickens suggests that between March and August there probably was an increase in the transmission rate of SLE virus. This increased rate coincided with the breeding period of birds in the area. An isolation of St. Louis encephalitis virus, confirmed by the Trinidad Regional Virus Laboratories, was made from a mockingbird nestling in August. The isolate seems to be closely related to Tr 9464 and Ja 7532 viruses, which are both closely related to the Parton strain of SLE virus.(AU)

Arbovirus surveillance in Jamaica

Following the outbreak of Eastern Equine Encephalomyelitis in Jamaica in the latter part of 1962, a surveillance was set up involving mosquitoes, birds, rodents and equines. About 650 birds have been collected to date. Sera from these were tested against EEE, St. Louis and Cache Valley viruses. Many inoculations were made for virus isolation. Serological results: 10 positive to EEE, 22 positive to SLE, and 15 positive to Cache Valley (12 wild birds and 3 chickens). Three viruses were isolated. From August 1963 - July 1964, 511 pools of mosquitoes were inoculated resulting in the isolation of 3 viruses. These are not yet identified. During the past year 223 equine sera were tested for EEE antibodies, 23 of these were positive. One hundred and sixty-six rodents were collected; organs and sera were inoculated for virus isolation and sera tested against Cache Valley, SLE and EEE viruses. There were seven positives for Cache Valley virus, 1 for EEE and 5 for St. Louis virus. No virus isolation has been made. Since June 1964, a bird banding programme has been set up in the parishes of St. Thomas and Portland. The chief objective of this programme is to determine the infiltration of the EEE and other viruses by migrant North American birds into the island. Birds are netted bled and released. These are recaptured and re-bled. Sera are inoculated for virus isolation and tested serologically for EEE antibodies. To date, 15 paired sera have been collected (AU)

St Louis encephalitis virus isolations in Trinidad, West Indies, 1953-1962

In summary, over the past 9.5 years, there have been 19 isolations of St Louis encephalites virus in Trinidad. These have been spread out as follows: 1955, three isolations; 1956, one; 1958, seven; 1960, seven; and 1962, one. One virus strain came from a human being, five came from five species of birds, and 13 came from nine species of mosquitoes (Summary)