Rabies in Marmosets (Callithrix jacchus)
Rabies in Marmosets (Callithrix jacchus)
A new Rabies virus variant, with no close antigenic or genetic relationship to any known rabies variants found in bats or terrestrial mammals in the Americas, was identified in association with human rabies cases reported from the state of Ceará, Brazil, from 1991 to 1998. The marmoset, Callithrix jacchus jacchus, was determined to be the source of exposure.
Canine rabies has been controlled in southern Brazil, and cases have declined in the rest of the country. Under these new epidemiologic conditions, the existence of rabies in other species, until now eclipsed by the rabies cycle in dogs, has become evident.
In the state of Ceará, for example, 13 human deaths due to rabies transmitted by wildlife were reported from 1991 to 1998 (Figure 1). Surveillance data indicated that these deaths were the consequence of exposure to bats (four deaths), a crab-eating raccoon (Procyon cancrivorous [guaximín]; one death), and the white-tufted-ear marmoset (Callithrix jacchus jacchus [sagüí]; eight deaths). These last eight cases constitute the first report in which one species of the order Primate is a primary source of rabies infection for humans in a restricted geographic area.
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Figure 1. Map of Brazil indicating the location of Ceará State.
The marmoset, C. j. jacchus or sagüí, is a small diurnal primate that feeds on insects, fruits, and tree exudates. Members of this species are commonly captured to keep as pets in Ceará, as other marmosets are in the rest of the country (Figure 2). The sagüí is also present in the neighboring states of Piauí and Pernambuco (Figure 1). These marmosets are highly adaptable to different habitats and can be found on plantations and in urban parks.
(Enlarge Image)
Figure 2. A pet marmoset with its owner.
In one of the eight human rabies cases associated with C. jacchus, the animal approached the house and attacked the owner. In another case, the marmoset was raised as a pet. In the other cases, the exposure occurred during attempts to capture the animals. Seven of these cases occurred in the coastal region, where the sagüí is more abundant. Epidemiologic investigations and surveillance data suggested the emergence of a rabies cycle in which this marmoset was the main transmitter. The public health importance of this situation is reflected not only in reported human deaths, but also in the fact that in Ceará an average of 25 persons per month seek rabies postexposure prophylaxis for marmoset and other primate bites.
To better understand the underlying factors that could be responsible for the emergence of these unusual epidemiologic events and to help identify a possible reservoir of this Rabies virus (RABV) circulating in Ceará, three rabies field isolates--two obtained from humans, each bitten by a different sagüí (Brhm4097 and Brhm4108), and one from a rabid sagüí (Brsg4138) in 1998--were antigenically and genetically characterized.
A new Rabies virus variant, with no close antigenic or genetic relationship to any known rabies variants found in bats or terrestrial mammals in the Americas, was identified in association with human rabies cases reported from the state of Ceará, Brazil, from 1991 to 1998. The marmoset, Callithrix jacchus jacchus, was determined to be the source of exposure.
Canine rabies has been controlled in southern Brazil, and cases have declined in the rest of the country. Under these new epidemiologic conditions, the existence of rabies in other species, until now eclipsed by the rabies cycle in dogs, has become evident.
In the state of Ceará, for example, 13 human deaths due to rabies transmitted by wildlife were reported from 1991 to 1998 (Figure 1). Surveillance data indicated that these deaths were the consequence of exposure to bats (four deaths), a crab-eating raccoon (Procyon cancrivorous [guaximín]; one death), and the white-tufted-ear marmoset (Callithrix jacchus jacchus [sagüí]; eight deaths). These last eight cases constitute the first report in which one species of the order Primate is a primary source of rabies infection for humans in a restricted geographic area.
(Enlarge Image)
Figure 1. Map of Brazil indicating the location of Ceará State.
The marmoset, C. j. jacchus or sagüí, is a small diurnal primate that feeds on insects, fruits, and tree exudates. Members of this species are commonly captured to keep as pets in Ceará, as other marmosets are in the rest of the country (Figure 2). The sagüí is also present in the neighboring states of Piauí and Pernambuco (Figure 1). These marmosets are highly adaptable to different habitats and can be found on plantations and in urban parks.
(Enlarge Image)
Figure 2. A pet marmoset with its owner.
In one of the eight human rabies cases associated with C. jacchus, the animal approached the house and attacked the owner. In another case, the marmoset was raised as a pet. In the other cases, the exposure occurred during attempts to capture the animals. Seven of these cases occurred in the coastal region, where the sagüí is more abundant. Epidemiologic investigations and surveillance data suggested the emergence of a rabies cycle in which this marmoset was the main transmitter. The public health importance of this situation is reflected not only in reported human deaths, but also in the fact that in Ceará an average of 25 persons per month seek rabies postexposure prophylaxis for marmoset and other primate bites.
To better understand the underlying factors that could be responsible for the emergence of these unusual epidemiologic events and to help identify a possible reservoir of this Rabies virus (RABV) circulating in Ceará, three rabies field isolates--two obtained from humans, each bitten by a different sagüí (Brhm4097 and Brhm4108), and one from a rabid sagüí (Brsg4138) in 1998--were antigenically and genetically characterized.