Study of Visceral Leishmaniasis (Kala-azar) in Children of Nepal

Introduction: Visceral leishmaniasis (VL) or Kala-azar is a potentially fatal vector-borne (sand fly phlebotomies spp) zoonotic disease caused by a protozoan parasite, Leishmania donovani. In Nepal, the disease is restricted to the Eastern Terai region which lies adjacent to the Bihar state of India. Although leishmaniasis is regarded as a significant health problem in Nepal by the Ministry of Health, there is no active case detection programme in the country. Objective: Objectives of this study were to determine the up-to-date morbidity and mortality trend for VL in children of Nepal. Method: The epidemiological surveillance team from the NZFHRC visited to eight zonal hospitals in Terai region during the month from September to December of each year 2003 to 2007. The morbidity and mortality data up to the year 2007 were collected every year. The team has also collected 66 blood serum samples of which 18 samples from children were collected for the diagnosis. Results: A total 25890 cases with 599 deaths were reported during the year 1980-2006. The case fatality rate (CFR) varied from 0.23% to 13.2%. Districtwise analysis showed that, during 2003, highest incidence was in Mahottari district (184/100,000), followed by Sarlahi (100/100,000) and Sunsari (96/100,000). The highest CFR was in Dhanusha (2.9%) followed by Bara (2.4%) and Saptari (2.0%). Majority (70.9%) of persons affected by VL were aged 15 years and above, followed by 10-14 years (13.9%), 5-9 years (11.9%) and 1-4 years (3.3%). VL cases recorded from different district of Nepal for the year 2004, 2005, 2006 and 2007 are recorded. CFR for the year 2004, 2005, 2006 and 2007 were 3.2%, 3.7%, 16.67% and 11.42% respectively. Conclusions: There should be regular surveillance research work to be carried out in endemic area. Mass public health education, to make the people aware about preventive aspects of the disease is important. The possibility of the existence of animal reservoirs as zoonotic disease should also be considered. This disease is very much serious in children below 15 years of age both in male and female, therefore it is essential to have paediatrician post at least in all VL six endemic districts.


Introduction
N epal, together with India, Bangladesh, Sudan and Brazil constitutes the fi ve countries of the world where more that 90% of VL occurs 1 .VL is endemic in 14 districts of central and eastern regions of Nepal.Nearly six million people residing in these districts are at risk of acquiring this disease.VL in Nepal mostly occurs in the eastern and central Terai regions, bordering with the Bihar State of India, although scattered outbreaks have also been reported in the mid-western and western Terai.
During mid 1970's, when the insecticide-spraying program was stopped; it resulted in higher incidence of VL in the late 1970's.The infection is believed to be introduced from the Indian state of Bihar where an epidemic of Kala-azar took place in 1977 2,3 .
In Nepal, VL is primarily a disease of the poorest of the poor 3,4 .These people usually live in the mud houses having cracked walls and damp fl oors, which constitute excellent condition for attraction and hiding of sandfl ies.Moreover, majority of these people sleep outside of their houses during the summer, without bed nets, which is most favourable situation for the sandfl y to bite and transmit the infection.Although VL cases are still being reported at lower rate in Nepal since 1998 but this might have also been due to out-migration to the Middle-East counties for employment and carry back infection into Nepal. 5,6Regarding cases of Post Kalaazar Dermal Leishmaniasis (PKDL), as it is sequel to kala-azar treatment; abundant cases are found here in Nepal 7 .
The parasite species causing VL in Nepal is Leishmania donovani 8 .In addition, L. tropica, and L. major might be occurring in Nepal as they are common in other parts of South-Asia.Regarding the vector, VL has been reported to be transmitted in Nepal by the endophoiles; P. argentipes, P. papatasi, P. sergenti, and Sergentomyia babu [9][10] .
In Nepal, VL primarily manifests as fever, anaemia, hepato and spllenomegay, resulting in death if it is untreated.The diagnosis of VL in Nepal is largely based on clinical signs and symptoms, usually combined with positive formal-gel test 11 .At present, the most widely used immunological tests to detect VL in Nepal are the nitrocellulose dipstick test that detects antibody to the recombinant amastigote antigen K39 (rK39), direct agglutination test, and latex agglutination test 10,11 .
This study was thus undertaken to determine the up-to-date morbidity and mortality data for visceral leishmaniasis particularly in children of Nepal 12 .

Materials and Methods
The survey team from the NZFHRC visited during the month of September to December of each year 2003,  2004, 2005, 2006 and 2007 respectively in eight zonal hospitals in the Terai region.The morbidity and mortality data from 1980 up to the year 2007 were collected from the above mentioned Zonal and District Hospitals of Nepal.During the year 2007 September to December month NZFHRC team members and researcher collected sixty six (66) blood serum samples of which eighteen (18) samples from children and rest forty eight (48) samples from adult male and female patients and eighteen (18) bone marrow samples of which six (6)  samples were from children were also collected for the Aldehyde test to confi rm the diagnosis.

Incidence and CFR
In Nepal Visceral Leishmaniasis (VL) cases were fi rst recorded in 1980 with the incidence rate of 1.5 per 100,000 populations and case fatality rate of 5.9%.Since then VL cases are showing rising trend.However, the case fatality rate (CFR) has been fl uctuating.The incidence of VL was highest in 2003 and highest CFR in 1982 (Fig: 1).

Seasonal distribution
The seasonal data pattern was interpretted and tabulated.Highest numbers of cases were reported during the rainy season (June to August) and lowest during the winter (September -December) and started to have increased during (Jan.-May) (Fig. 2).Of the total eighteen (n=18) suspected patients with Kala-azar were tested by aldehyde and bone-marrow methods.Among them, 33.33% (6/18) were positive for aldehyde test only and 83.3% (5/6) for bone-marrow only.Of the eighteen (n=18) tested by both methods, 11.1% (2/18) were bone marrow positive but aldehyde negative and 0.0% (0/18) by both tests.The age related pattern was nearly uniform except among children aged below nine years, where only 11.1% could be confi rmed by any of these tests.

Discussion
In comparison with the baseline incidence data in the epidemiological and socio-economical surveillance report on Leishmaniasis in Nepal, for 1996 and 1997, the number of kala-azar cases has approximately doubled during 1998-1999.Bista (1998) 5 also observed that the number of reported cases had increased dramatically over the past fi ve years and that the current situation could be considered epidemic in the affected areas.Out of total sixty six (n=66) serum samples collected forty (n=40) were tested by aldehyde test only out of which 32 (80%) found positive.Similarly, seven out of eight (87.5%) were found positive for bone marrow test and four out of eighteen (22.2%) tested positive for both aldehyde and bone marrow methods.In Nepal, VL primarily manifests as fever, anaemia, spleno-and hepatomegaly, resulting in death if it is untreated.The diagnosis of VL in Nepal is largely based on clinical signs and symptoms, usually combined with positive formal-gel test.Reference laboratories and regional hospitals routinely use some serological tests.The most important factor responsible for this resurgence seems to be discontinuation of the DDT spraying campaigns in many areas, failure of detection of diseases among people, inaccessibility or unaffordability of poor to the treatment and lack of awareness among these people about the preventive aspects of the disease.Therefore, extensive spraying in all endemic areas is the need of the time.In the meantime, measures like popularising use of bednets (Government may consider providing it on subsidy for the population in affected areas), extensive surveillance, prompt diagnosis and treatment along with effective health education should be undertaken to avoid future epidemic.They should also be taught to protect while sleeping, take measures to contain sandfl y growth and habitat in cracks & dampness in their houses, maintain hygiene to keep the surrounding free of sandfl y.

Conclusion
Visceral leishmaniasis (kala-azar) cases are suggesting an increasing trend in Nepal.There should be regular surveillance research work to be carried out in both epidemic and non-epidemic districts of the country.Mass public health education, to make the

VL Affected Districts
VL Affected Districts people aware about preventive aspects of the disease is important.The possibility of the existence of animal reservoirs as zoonotic disease should also be considered and checked out for better control measures.This disease is very much serious in children below 15 years of age both in male and female, therefore it is essential to have paediatricians posted at least in all six VL endemic districts of eastern terai region.There should be a special refresher training regarding the clinical therapy given to the paediatricians.This will help in decreasing the mortality of the children due to kala-azar.

Fig 4 :
Fig 4: VL Cases recorded in Different Districts of Nepal during the Year 2005.

Fig 5 :Fig 6 :
Fig 5: VL Cases Recorded in Different District of Nepal from Aug to Dec 2006.

Table 4 .
It has been found that children are more affected than adult.During the year 2003, out of the 1345 Kalaazar cases none (0%) were found in infants.In one to four years age group it was seen in 3.3% and 11.9% in the age group of fi ve to nine years age.It was found in 13.9% in the ten to forteen years age group and 65.1% in 15-59 years and 5.8% in >60 years.However, CFR did not follow any trend specifi c to age/sex.andFig5.Most affected districts were Mahottari, Dhanusha, Saptari and Sunsari respectively.

Table 1 :
District wise Kala-Azar Incidence and CFR 2001, 2002 & 2003.deaths of Makwanpur and 1 case & 1 death of Chitwan, in 2003, are not shown in the table.

Table 2 :
VL Cases recorded in Different Districts of Nepal during the year 2004.

Table 3 :
VL Cases recorded in Different Districts of Nepal during the Year 2005.

Table 4 :
VL Cased recorded in Different District of Nepal from Aug to Dec2006.

Table 5 :
VL Cases Recorded in Different District of Nepal during the year 2007.

Table 6 :
Aldehyde and Bone Marrow Test Result for Kala-Azar in Siraha District Hospital.