Leptospiral carriage by Mice and Mongooses on the island of Barbados

Leptospirosis is a zoonotic disease, maintained by chronic infection of the kidneys of reservoir animals, usually small mammals. Infection in humans is acquired from direct or indirect exposure to the urine of infected animals. Leptospirosis has a high incidence in tropical regions, and has been studied extensively in several Caribbean countries. We studied the carriage of Leptospira serovars by two small mammals which are potential maintenance host of the disease in Barbados. A total of 136 mongooses (Herpestes auropunctatus) and 97 mice (Mus musculus) were caught in live traps. Leptospiral antibodies were detected by microscopic aggutination test (MAT) using antigens representing 12 serogrouops, and kidney tissues were inoculated into polysorbate medium for isolation of leptospires. The seroprevalence (at a titre of o 100) in mice was 28.2 percent (24/85, 95 percent CI 19.0, 39.1) and in mongooses 40.7 percent (48/118, 95 percent CI 20.1, 39.0) and from 4 mongooses ( 2.9 percent, 95 percent, CI 0.8, 7.4). Mouse isolates were identified as serovars arborea (17) and bim (7). As in other parts of the world, common house mice (Mus musculus) represent a significant reservoir of leptospirosis. Although carriage of the Ballum serovar, arborea, was not unexpected, this represents the first time that an animal reservoir of serovar bim has been identified. This is significant because bim causes about 63 percent of human leptospirosis in Barbados, and control efforts and education for prevention can now be targeted at a specific reservoir. (AU)

Field evaluation of baits and baiting strategies for delivering oral vaccine to mongooses in Antigua, West Indies

A field of study was conducted on Antigua, West Indies to determine the feasibility of delivering an oral rabies vaccine or population control agent to free-ranging mongooses (Herpestes javanicua). Two biomarkers (tetracycline hydrochloride [THCL] and Dupoint Oil Blue A dye) and two bait types (Dupont polymer fish meal and polyurethane foam) were used to bait three study sites. Four hundred polymer baits containing both biomarkers were distributed at 36 central point bait stations (11 baits/station) on an 80 ha study site (5 baits/ha); 69 percent of the mongoose population consumed one or more baits. Two thousand baits containing THCL and 400 baits containing DuPont dye were distributed on two additional 100 ha study sites (24 baits/ha). Polymer fish meal baits were used on the first site and polyurethane baits on the second site. Based on the presence of biomarkers in bone or soft tissue, 96 to 97 percent of the mongooses at both sites consumed at least one bait. We conclude that oral baiting of mongooses is a feasible method for delivery of vaccines for the control of rabies in this species (AU)

Evaluation of baits for oral rabies vaccination of mongooses: pilot field trials in Antigua, West Indies

A field study was conducted on the island of Antigua, West Indies, to evaluated baits for delivering an oral rabies vaccine to the small mongoose (Herpestes auropunctatus). Tracking tiles were used to determine that mongooses were nonselective and took both egg-flavored polyurethane baits and fish-flavored polymer baits containing several different food materials. A high proportion of baits were taken the day of placement with minimal disturbance by nontarget species. DuPont Oil Blue A dye was an effective short-term biomarker for use in baits;based on its subsequent detection in mongooses, some of the population had consumed and not cached or discarded baits. Central point baiting stations showed promise as an alternative delivery technique (AU)

A sero-epidemiological survey of leptospirosis among Jamaican human and animal populations

To date, relatively little research on leptospirosis has been undertaken in Jamaica and the Caribbean as a whole. This is despite the apparent role of this disease as a zoonosis. The major objective of this survey was that of determining the current status of leptospirosis in the Jamaican human, livestock and sylvatic populations through a sero-epidemiological approach. Sera for this survey were randomly selected from the ongoing National Brucelosis Control Programme serum banks at the Veterinary Diagnostic laboratory at Hope, in addition to sera collected island-wide on special field trips. Leptospiral titres were determined by the Microscopic Agglutination Test (MAT), the standard reference procedure as described by Galton et al and modified by Cole et al. All sera were tested against the following live leptopiral antigens: abramis, autumnalis, canicola, ictero-haemorrhagiae, hardjo, grippotyphhosa, jules, pomona, portland-vere, monymusk, bog-vere and pyrogenes. A presumptive positive reaction was based on a 1:100 dilution or greater to any of the test antigens used. Leptospiral determination of the approximately 12,000 sera used indicated high seroprevalence rates for all species studied. Seroprevalence rates were being reported in poultry for the first time in Jamaica. The most frequent presumptive infecting serovars found in this particular survey were portland-vere, canicola, icterohaemorrhagiae and jules. These prodominated in nearly all the species surveyed. The serovar jules is unique to Jamaica and its comparatively high prevalence in both the human and animal population indicates a necessity for further investigation. The highest yearly seroprevalence rate (46 percent) was recorded for 1986. There was no significant differences observed in sex-related seroprevalence rates for humans while age, geographical and occupational seroprevalence relationships were significant. The periods accounting for the highest precipitation had correspondingly the highest leptospiral seropositive rates. This study has confirmed that leptospirosis is both an endemic and enzootic condition in Jamaica and that the dimension of the problem may be greater than current information suggests. The results further indicate that serological surveys are useful tools and provide a pragmatic approach to the greater understanding of the epidemiological patterns of leptospirosis. An intensified national ongoing leptospirosis control programme along with an assessment of the economic impact of this disease on livestock production and its public health significance are urgently needed (AU)

Pathogenic leptospira isolates from the Caribbean Island of Barbados

This paper lists all the known pathogenic leptospira isolates made on Barbados up to December 31, 1981. Only 17 of the total of 78 have already been reported on. The 78 isolates were obtained from humans, dogs, rats, mongooses and a mouse, and the serogroups to which they belonged were Icterohaemorrhagiae, Autumnalis, Ballum and Canicola. On Barbados, serogroup Autumnalis is an important human pathogen, and rats are an important reservoir of leptospires. The investigation and isolation of leptospires on Barbados has until recently been sporadic, dependent on the interst and enthusiasm of a few individuals, and restricted by a shortage of money and manpower. During 1964 and 1965 the Barbados Ministries of Health and Agriculture and the U.K. Ministry of Overseas Development investigated the impact of rodents on the health and economy of Barbados. As part of this study, leptospires wer isolated by taylor and identified to serogroup by Turner. The results are recorded in an unpublished document (Taylor, 1965). Between 1971 and 1981, Leptospira were isolated from rodents, mongooses (Herpestes auropunctatus), dogs and amphibians at the Barbados Veterinary Diagnostic Laboratory (VDL) by Jones and Everard. Twenty-three of these isolates survived and were identified by Myers and Dr. C. R. Sulzer of the Centers for Disease Control (CDC), Atlanta, U.S.A. Seventeen of the 23 have been reported on(Jones, 1974; Myers and Jones, 1975; Damude et al., 1979a), and they are included here for the sake of completeness. In 1979 10 Autumnalis isolates made by Taylor in 1964-1965 were reactivated from liquid nitrogen, cultured, and identified to serovar by Everard. The identifications were confirmed by Dr. Sulzer. The remaining 33 isolates in Taylor's series were not reactivated. From November 1979, isolates were made by Everard from patients at Queen Elizabeth Hospital (QEH), Bridgetown, and were identified to serovar by Dr. Sulzer. These studies have provided all the isolates recorded here. The Leptospiral Serotype DistributionList (Galton, 1966) do not have an entry for Barbados, but the supplement to the 1966 edition covering the period July 1966 to July 1973 (Sulzer, 1975) lists Autumnalis fort-bragg isolated from a rat, and Canicola, Ballum and Icterohaemorrhagiae from specified hosts. Barbados obtained up to December 31, 1981. Only 17 of the isolates have been previously reported. All the Leptospira isolates recorded from Trinidad, Grenada and St. Vincent up to the end of 1979 are listed by Everard et al. (180). (AU)

Rabies serum neutralizing antibody in mongooses from Grenada

During a four year study on Grenada, 4,754 mongooses were examined, of which 100 (2.1 percent) were rabid. Of 1,675 mongooses tested for rabies serum neutraslizing (SN) antibody, 498 (30 percent) were positive. During these four years (1971-74) the antibody prevalence rate increased from 20.8 percent to 43.3 percent, whereas the number of rabid mongooses decreased from 3.5 percent to 0.6 percent. Naturally acquired antibody was monitored in 20 captive mongooses for up to 35 months, and it was still circulating in 18 when monitoring ceased. The highest titre recorded was 1:1,400, and the rate of fall was highest in mongooses with high initial titres. High titres of naturally occuring antibody suggest recent rabies activity. 14 mongooses vaccinated parenterally with 1.0 ml of attenuated ERA vaccine showed substantial increases in antibody titres; most had titres greater than 1:1,000 one month later and maintained a high titre for several months. The highest recorded was 1:34,800. The virus titres of brain material from rabid mongooses ranged from 10 to the power 1.8 to 10 to the power 4.3 and, in some cases, were only slightly lower than those of salivary gland tissue (range 10 to the power 1 to 10 to the power 5.6) (Summary)

Four new leptospira serotypes from Trinidad

This paper reports four new Leptospira serotypes from the West Indian island of Trinidad. They are princetown and navet from humans, caribe from Rattus, and mangus from the mongoose, herpestes auropunctatus (AU)

Leptospirosis in Trinidad and Grenada, with special reference to the mongoose

In Trinidad, six leptospira isolates were made from 957 febrile patients between 1968 and 1972. In addition CF antibodies were detected in 6.6//of febrile patients and human survey sera collected during this period. In 1972 alone, 10.4//(38/363) of sera examined had CF titres consistent with positive exposure to the disease. Grenada does not report leptospirosis, but the disease is common in mongooses in both Trinidad and Grenada. Serogroups Icterohaemorrahagian, Pomona and Canicola are present in Grenada with 35.2//of mongooses examined being seropositive. Five Canicola strains of Leptospira were isolated from mongooses in Trinidad, and serological studies showed that this was most common serogroups from mongooses on the island. A total of 31 strains recorded from at least seven different serogroups and eight named serotypes have been isolated from humans, rats and mongooses in Trinidad. Human leptospirosis is probably more common in the Caribbean than the medical records indicate. (AU)

The mongoose as a reservoir of leptospirosis - abstract

This paper presents the data on the incidence of leptospirosis in the Southern Caribbean and gives special emphasis to the mongoose which is a known carrier of the disease. Leptospira isolates from blood in man and blood and kidney tissue in animals have been maintained in tryptose phosphate broth cultures. Serological studies have been undertaken by both complement fixation (CF) and microscopic agglutination (MA) tests. Reports from United States indicate that only 20 percent of human leptospirosis cases are immediately recognized; common diagnoses include meningitis, hepatitis, nephritis, fever of unknown origin, and influenza (Busch, 1970). Symptoms are inconsistent, with the classical clinical jaundice of Weil's disease being reported in less than 50 percent of cases. In the eleven years 1961 - 1971, there was an average of 81.7 reported cases of leptospirosis per year in the United States. The annual average for Barbados was 14.2 taken over the past five years, and for Jamaica 9.8 taken over the past six years. Trinidad has reported only an average of 0.8 cases per year in the last five years, while Grenada does not report leptospirosis at all. Our studies indicate that the infection is common in mongooses in Grenadam with high anti-body titres (<: 100 by MA test) in 35.2 percent in (152 of 432) animals examined. Serologic studies indicate three serogroups are present: Icterohaemorrhagiae (36.8 percent), Pomona (21.0 percent), and Canicola (6.6 percent). The remaining 35.6 percent positive samples suggest a history of mixed infections with icterohaemorrhagiae predoninating. In Trinidad, the proportion is higher, with 51.1 percent (24 of 41) mongooses positive; serotype canicola predominates, and this is confirmed by leptospiral isolates from kidney tissue. Between 1968 and 1971, blood cultures from 694 clinical patients in Trinidad gave five leptospira isolates; and, in addition, CG antibodies were detected in 5.1 percent ( 48 of 934) of human survey sera. Including earlier studies, a total of eight serotypes, two of them new sub-serotypes, have been recorded from six serogroups. Although infected water, domestic animals, and periodomestic rodents are usually considered to be the sources of human leptospirosis the high prevalence of infection in mongooses, coupled with their behaviour and distribution suggests that they may play an important role in the epidemiology of the disease; and this has hitherto been insufficiently emphasized in the Caribbean (AU)

Mongoose rabies in grenada - abstract

The programme aimed at eradicating mongoose rabies from Grenada is discussed. So far this programme has not been successful. Results of the examination of over 500 specimens from Grenada collected in 1966 and 1967 indicate that the virus is more active on the Caribbean side of the island than on the Atlantic side. They also suggest that transmission of rabies virus is more intense during the dry seasons. The implications of these findings for a more successful operation in the future are discussed(AU)