The following background data on plague in Madagascar were abstracted from Gideon www.GideonOnline.com and the Gideon e-book series. [1,2] (Primary references are available on request)

Time and Place:

– Plague was first described in Madagascar in 1898, with cases in the harbor of Tamatave (Toamasina).

– The first epidemic occurred in Majunga in 1902 (142 fatal cases during May to July of that year).

– Subsequent outbreaks were reported in Majunja in 1907 (49 fatal cases), 1924 and 1928.

– The disease reached the central highlands in 1921, and remains endemic to this area at elevations above 800 m.

– Outbreaks of pneumonic plague were reported during 1921 to 1935; and in 1957 (northeast region).

– Plague was first reported in port areas of Madagascar in 1898; with later spread to the high plateau in 1921.

– During 1989 to 1992, 93% of cases were reported from “the plague triangle” located in the Central Highlands and delimited by Ambatondrazaka, Miarinarivo and Fianarantsoa.

Biology and transmission:

– Reservoirs implicated in transmission include the shrews (Suncus murinus) and rats (Rattus rattus).

– Infection has also been identified in hedgehogs (Tenrec ecaudatus).

– Possible flea vectors include Paractenopsyllus pauliani, Synopsyllus fonquerniei and Xenopsylla cheopis.

Incidence:

Two major waves of plague have been reported – with peak incidence in 1932 (3,656 cases) and 1997 (2,863 cases). See graph:

– 10,471 cases were reported during 1935 to 1949 ; 9,227 (448 fatal) during 1957 to 1986; 5,896 (493 fatal) during 1980 to 1997; 11,673 (950 fatal) during 1987 to 2001.

– Of 5,927 suspected cases reported during 1989 to 1995, 1,337 were bacteriologically-confirmed, with a case-fatality rate of 19%.

– 1,702 suspected cases (515 confirmed, 47 fatal) were reported in Mahajanga during 1995 to 1998.

– 91.3% of these cases were characterized as bubonic (67.8% of these involving the inguinal region).

Africa accounts for most of the world’s plague deaths. >=50% of these deaths are reported by Madagascar. See graph:

Seroprevalence surveys:

<1.5% to 15.5% in Majanga City (1997 publication) 0.61% of persons in Mahajanga (anti-F1 antibody, 1999) 3.2% of market vendors in Antananarivo (anti-F1 antibody, 1999) Notable outbreaks: 1982 (publication year) - An outbreak (9 cases) was reported in Tananarive. 1991 - An outbreak was reported in Majunga. 1995 - An outbreak (108 confirmed and presumed cases) was reported in Mahajanga city. 1997 - An outbreak (2,863 cases, 176 fatal) was reported. 1998 - An outbreak was reported in a hamlet in the Ikongo district. 2008 - An outbreak (7 deaths) of pneumonic plague was reported in Toamasina. 2010 - An outbreak (31 cases, 1 fatal) was reported in La Libertad. 2011 - Outbreaks (200 cases, 60 fatal) were reported, including Antananarivo (3 fatal cases) and Antsiranana (16 fatal cases). (outline of Gideon Graph module - see https://www.gideononline.com/wp-content/uploads/Gideon-Graphs.pps )

References:

1. Berger SA. Infectious Diseases of Madagascar, 2011. 49 pp, 47 graphs, 1,029 references. Gideon e-books, https://www.gideononline.com/ebooks/country/infectious-diseases-of-madagascar/

2. Berger SA. Plague: Global Status, 2011. 95 pages, 101 graphs, 485 references. Gideon e-books, https://www.gideononline.com/ebooks/disease/plague-global-status/