[Leish-l] FW: PRO/AH/EDR> Leishmaniasis, canine - Argentina: (CN)

Thu Mar 24 20:35:28 BRT 2011

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From: ProMED-mail <promed at promed.isid.harvard.edu>

Date: 2011/3/23
Subject: PRO/AH/EDR> Leishmaniasis, canine - Argentina: (CN)
To: promed-ahead-edr at promedmail.org

LEISHMANIASIS, CANINE - ARGENTINA: (CORRIENTES)

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Date: Sun 20 Mar 2011

Source: El Litoral [in Spanish, trans. Mod.JG, edited]

<http://www.ellitoral.com.ar/leer_noticia.asp?IdNoticia=158479>

The arrival of autumn and the consequent temperature reduction may

not have direct consequences on the leishmaniasis outbreak that is

currently affecting the city of Corrientes since the beginning of this

year [2011]. According to specialists, the risk for transmission and

spread of the disease will still be high.

"Even though temperatures have now come down, this does not mean a

risk reduction; it is also necessary that people maintain good hygiene

in their households in order to prevent proliferation of both the

sandfly responsible of transmitting leishmaniasis, and the dengue

fever mosquito", declared this week Mr Carlos Frette, secretary of

health and environment for the municipality of Corrientes.

It is worth mentioning that to date this year [2011], 31 positive

cases of canine visceral leishmaniasis have been confirmed in the

city. New cases may be confirmed in the next days, after samples were

taken in the Juan de Vera, Centro, Fray Jose de la Quintana, and San

Cayetano communities.

--

Communicated by:

ProMED-mail

<promed at promedmail.org>

[The city of Corrientes can be located on the HealthMap/ProMED-mail

interactive map of Argentina at <http://healthmap.org/r/0C3B>. -

Sr.Tech.Ed.MJ]

[The phlebotomine sandflies, _Phlebotomus_ spp (Old World sandflies)

and _Lutzomyia_ spp (New World sandflies), are members of the family

Psychodidae. These flies are confined primarily to the tropical and

subtropical regions of the world. Members of these genera are tiny,

moth-like flies, about 1.5-4 mm long. The legs are as long as the

antennae, comprising 16 segments that often have a beaded, hairy

appearance. They are commonly known as sandflies, moth flies, or owl

midges. The key morphologic feature for identification is that the

body of the sandfly is covered with fine hairs. The females have

piercing mouthparts and feed on blood of a variety of warm-blooded

animals, including humans. Many species feed on reptiles. Male

sandflies suck moisture from any available source and are even said to

suck perspiration from people. Sandflies tend to be active only at

night and, in contrast to black flies, are weak fliers; their flying

is deterred by air currents, even slight ones. During the day,

sandflies seek protection in crevices and caves, among vegetation, and

within dark buildings. They often seek protection within rodent and

armadillo burrows; these mammals can serve as reservoir hosts.

Visceral leishmaniasis is a chronic, severe, protozoal disease of

humans, dogs, and certain rodents, characterized by cutaneous or

mucocutaneous lesions, lymphadenopathy, weight loss, anemia, lameness,

renal failure, and occasionally epistaxis or ocular lesions.

Canine leishmaniasis is a zoonotic disease, and dogs act as a

reservoir of the parasite for humans where there is a competent

vector.

The incubation period is quite variable, ranging from 3 months to

several years. The clinical features vary widely; main clinical

presentations are skin lesions, loss of weight or poor appetite, local

or generalized lymphadenopathy, ocular lesions, renal failure,

epistaxis, lameness, and anemia. Occasionally, some dogs have chronic

diarrhea or liver failure. The most common cutaneous lesions are

alopecia with severe dry desquamation, usually beginning on the head

and extending to the rest of the body. Other animals develop chronic

ulceration, located particularly on the head and limbs. The signs

invariably show a slow, progressive evolution.

The results of blood and urine tests also vary greatly. Most animals

have a polyclonal hyperproteinemia. Non regenerative anemia is present

in 50 percent of dogs. Some animals show leukopenia, whereas others

have leukocytosis. In animals with renal lesions, it is also usual to

find increased plasma urea and creatinine, proteinuria, and hematuria.

The most reliable diagnostic test for canine leishmaniasis is direct

observation of the parasite in bone marrow or lymph node smears. The

amastigotes appear as oval basophilic bodies (4 micrometer) in the

cytoplasm of macrophages. However, it is sometimes impossible to

detect the parasite in infected animals, especially in lymph node

smears. Serologic methods are useful in diagnosis; indirect

immunofluorescence and ELISA are widely used. The results of a

serologic test should be interpreted in conjunction with the clinical

picture. Although these tests are reliable, a few infected dogs remain

seronegative, and there are also seropositive dogs that never develop

the disease.

For treatment, the drugs of choice are the pentavalent antimony

derivatives, particularly N-methylglucamine antimoniate (80-100

mg/kg/day, IM (intramuscular) or SC (subcutaneous) [not approved for

use in dogs in the USA]) and sodium stibogluconate (75 mg/kg, SC, bid

[available only from the CDC in the USA]). During the 1st month, the

dog is treated with either drug and allopurinol (20 mg/kg, PO

(orally), sid (once a day); during the next 5 months, the dog is

treated with only allopurinol, which is less expensive and less

toxic.

Amphotericin B given IV (intravenously, 0.5-0.8 mg/kg, diluted in

10-60 mL of 5 percent dextrose given over 45 seconds every 48 hours to

reach a total cumulative dose of 8-15 mg/kg) or SC 2-3 times/week

(0.5-0.8 mg/kg added to 500 mL of 0.45 percent saline and 2.5 percent

dextrose for a total cumulative dosage of 8-26 mg/kg) has also been

effective.

Relapses after treatment are common with either protocol. In endemic

areas, rapid treatment of infected dogs, control of stray and homeless

dogs, and action against the insect vectors are recommended methods of

control.

Controlling the sandfly is important. Insecticide spraying of larval

habitat is usually not possible because of the difficulty of accessing

their breeding sites. Removal of dense vegetation discourages

breeding. Spraying of residual insecticides on surfaces in the home is

the main way to control sandflies; however, this is ineffective for

species that bite away from the home. Generally speaking, populations

of sandflies have been reduced as a result of intense mosquito control

programs.

So while this long bit of information is about canine visceral

leishmaniasis, it is probable this disease is on the move, northward,

and the significance of canine involvement may keep the zoonotic cycle

going longer than had been hoped.

Portions of this comment have been extracted from

<http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/71703.htm&word=leishmania>.

- Mod.TG]

[see also:

Leishmaniasis, outbreak - Argentina: (CN) corr. 20110224.0610

Leishmaniasis, outbreak - Argentina: (CB) 20110222.0584

2010

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Leishmaniasis, canine - Argentina: (CN) 20100211.0483]

.................................................sb/tg/mj/lm

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