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kala - azar occurs in 2 foci ( figure 1 ) and is caused by l. donovani . in the northern focus ( upper nile , jonglei , and unity states ) , phlebotomus orientalis is the vector ; in the southern focus ( parts of eastern equatoria state ) , p. martini is the vector ( 3,4 ) . although studies in eastern sudan have found domestic animals infected with the parasite ( 5,6 ) , whether these animals play a role as disease reservoirs has not yet been proven ; thus , transmission is still thought to be anthroponotic .
shaded areas represent those counties where primary cases were reported from january through june 2007 .
( adapted from world health organization , southern sudan health update , july  august 2007 . )
the disease was first reported from southern sudan in 1904 , and the first epidemic was documented in 1940 with a death rate of 80% ( 7 ) .
beginning in 1984 , an epidemic ( unrecognized until 1988 ) devastated the western part of upper nile state , ultimately causing 100,000 deaths in a population of 280,000 over a 10-year period ( 3 ) .
passive case - detection data on kala - azar in southern sudan , collected by the world health organization ( who ) since 1989 , indicate a cyclical pattern of kala - azar with considerable variation in the caseload from year to year ( figure 2 ) .
the dynamics presented in figure 2 also suggest that southern sudan is currently between epidemics and provide a warning that cases may rise dramatically in coming years . in 2006 , a total of 1,117 cases were reported , 65.4% of which were primary cases ; the remainder were either relapses or cases of post  kala - azar dermal leishmaniasis . from january through june 2007 ,
the 5 locations accounting for 74.2% of the primary cases in 2007 were malakal ( n = 83 ) , ulang ( n = 72 ) , nasir ( n = 63 ) , and kiechkuon ( n = 25 ) in upper nile state and lankien ( n = 79 ) in northern jonglei state .
since 2002 , the case - fatality rate recorded at healthcare facilities has been 4%6% .
total annual number of kala - azar cases in southern sudan reported to the world health organization , 19892006 .
these data likely underestimate the actual number of cases because healthcare providers do not always provide complete reports and many kala - azar patients never visit healthcare facilities .
epidemiologic modeling of data from upper nile state estimated that those who visited healthcare facilities from october 1998 through may 2002 represented only 55% of cases and that 91% of kala - azar deaths were undetected ( 8) .
health coverage is so minimal that some patients must walk for several days to access even the most basic healthcare services . despite the availability of different rapid diagnostic tests , most facilities used clinical diagnosis alone until recently . only a few had the supplies and equipment to confirm suspected cases through microscopic examination of lymph node aspirate , which has a sensitivity of only 53%65% ( 1 ) .
nongovernment healthcare providers and government of southern sudan  administered healthcare facilities thus had to confirm suspected kala - azar by direct agglutination test before they could receive a supply of the first - line treatment  sodium stibogluconate  from who through pharmaciens sans frontires . the use of the direct agglutination tests was required because of concerns about the sensitivity and specificity of the rk39 dipsticks in east africa ; a recent study suggests that these concerns were well founded ( 9 ) .
also , many facilities that had received dipsticks were not using them . until 2004 , many healthcare facilities did not have the equipment or skills to conduct direct agglutination tests , and blood samples had to be sent to kenya for analysis , which often led to treatment delays as long as 18 days .
now some healthcare facilities can analyze these samples internally and start treatment within 24 hours .
confirmed cases are treated with sodium stibogluconate at a dose of 20 mg / kg / day for 30 days .
recently , because of an increasing number of patients in upper nile state who were nonresponsive to sodium stibogluconate , mdicins sans frontires tested a combination of sodium stibogluconate and paromomycin , which would reduce treatment duration ( from 30 to 17 days ) and cost .
patient survival and initial cure rates were better than those for patients who received sodium stibogluconate monotherapy ( 10 ) .
however , completion of multicountry phase iii trials being conducted by the drugs for neglected diseases initiative ( www.dndi.org ) is eagerly awaited before the combination can be considered as an alternative .
amphotericin b , a second - line drug for treatment of kala - azar , is not yet available in southern sudan s facilities except in those run by mdicins sans frontires .
much remains unknown about the epidemiology of kala - azar in southern sudan ( 11 ) . in the absence of detailed information on risk factors (
cultural , demographic , epidemiologic , clinical , and geographic ) , use of long - lasting insecticide - treated nets seems a suitable method of prevention .
results from studies in northern sudan showed that insecticide - treated nets provided 27% protection from kala - azar ( 12 ) . whether similar protection can be achieved in southern sudan s disease - endemic areas requires confirmation because effectiveness is dependent on human and vector behavior ( 13 ) .
the return of stability to southern sudan has opened up new challenges and opportunities for kala - azar control .
large - scale population movement of susceptible or infected populations into kala - azar  endemic or nonendemic areas respectively , poses a major epidemic risk .
the healthcare systems are weak and rely on support from faith - based and nongovernment organizations , which need to be coordinated to ensure consistency in diagnosis , treatment , and prevention . as health infrastructure and human resources
are being built up , kala - azar will need to be addressed as an integral part of multifunctional healthcare delivery by government staff , but this requires training and the provision of essential supplies .
kala - azar falls under the mandate of the director general of preventive medicine within the ministry of health  government of southern sudan .
the ministry of health , with support from who and in conjunction with nongovernment organizations working on kala - azar , has embarked on a number of activities to strengthen case - management .
laboratory technicians in most referral facilities have now been trained on the direct agglutination test ; case - management guidelines have been updated ; the essential drugs list is being reviewed and expanded to include alternatives for second - line treatment ; and rk39 dipsticks are being distributed to peripheral health facilities to complement clinical diagnosis . with the revision of diagnosis and treatment guidelines ,
facilities are now able to obtain sodium stibogluconate by providing pharmaciens sans frontires with a positive rapid diagnostic test result , but they are encouraged to also take a blood sample for direct agglutination testing , as this is still considered more reliable ( 8) . meanwhile , the uk - based malaria consortium is providing long - lasting insecticide - treated nets to areas in jonglei and eastern equatoria , where malaria and kala - azar are co - endemic .
a strong presence of international donors and the southern sudan government s desire to quickly reconstruct the healthcare sector provide ample opportunity to reduce the incidence of kala - azar .
southern sudan is one of the areas in eastern africa most affected by visceral leishmaniasis ( kala - azar ) , but lack of security and funds has hampered control . since 2005 , the return of stability has opened up new opportunities to expand existing interventions and introduce new ones .