Epidemiology of Measles in Bale Zone South East Ethiopia 2019


 Background: - Measles remains causes of vaccine preventable death in children worldwide. Cases comes to health facilities after complication developed, and miss diagnosed as the complication than measles, which is a reason for under reporting of measles cases and number of reported cases represents small proportion of expected cases. While aim of this study is to analyze seven years (2013-2019) measles surveillance data of Bale zone and to indicate measles surveillance related gaps. Method: - Cross sectional study conducted from May 25-June 25/2019. Study population and sample was all measles cases reported to bale zone from 2013-2019. Data abstracted by reviewing seven years measles line list and case-based report by investigator using data abstraction check list. Data entered and analyzed by Microsoft excel. Tables, graph and percent presented the data. Result: - Overall, 4241 measles cases were reported with a case fatality of 3.07/1000 population. About 248(5.8%) were measles IgM confirmed. Mean age of the case patients were 7.15 and 2147 (50.6%) were males. The most affected age group were <4 years, 1685 (39.7%) of cases. The highest prevalence rate 141 / 100,000 populations reported in 2019.Unvaccinated and unknown status were 890(21%) and 731(17.2%). The highest numbers of cases reported from Ginir and Gololcha. Measles cases increase in autumn season of the year and reaches peak in May. Conclusion: - Measles is the major causes of morbidity and Mortality in Bale zone due to poor immunization coverage, 890(21%) of case patients were un vaccinated. Though community death is not included case fatality is high. Ginir reported the highest number of cases. Increasing vaccine coverage of the zone, early preparedness before annual cycle and strengthening measles case-based surveillance is mandatory.


Introduction
Measles is one of the most contagious diseases for humans caused by a virus in the family paramyxovirus, genus Morbillivirus. The incubation period for measles is 10-14 from exposure to symptom onset. Measles characterized by fever, malaise, cough, coryza, and conjunctivitis, followed by a maculopapular rash(1) (2). Complications of measles are most common among children younger than 5 years of age and 30% of reported measles cases result in complications such as pneumonia, diarrhea and encephalitis, and death (3).
Measles resulted in 90,000 and 110 000 deaths annually, in 2016 and 2017 respectively. In high income regions of the world, measles causes death 1 in 5000 cases, but greater than 1 in 100 may reach 25% will die in developing countries (8) . Measles is still a common and often fatal disease in developing countries (3). In 2013, 171,178 cases were reported from Africa region of world health organization WHO (11) and resulted in high attack rates among children less than one year. Measles is the leading cause of blindness in African children (3). According to a WHO report, measles still remains a public health priority disease and is associated with high morbidity and mortality. Most of the associated deaths occur in children aged ve years and younger. It is a leading cause of vaccine preventable death and endemic in low vaccine coverage countries. Measles follows a seasonal pattern, with increasing incidence in the dry season, i.e. from reported November to May (7) and in Ethiopia reach peak during the late-early part of the year (December to February) (12).
Measles is still one of the major causes of death and sickness of children in Ethiopia and outbreak reported annually (12) (4). Ethiopia is committed to achieve the elimination of measles by 2020 and measles incidence in Ethiopia is 50 cases/1,000,000 per year, which is above the national set targets for measles elimination by 2020 <1/1,000,000 per year in 2017(6). Case-fatality rate is between 3% and 6%; In certain high-risk populations, case-fatality rates as high as 30% have been reported in infants aged less than 1 year of age in Ethiopia(4). According to measles surveillance data analysis of 2012-2016 conducted in Oromia regional state of Ethiopia 26908 cases and 288 deaths were reported (13).
The risk factors for measles is inadequate vaccination, Malnourished, children with vitamin A de ciency and immunode ciency due to HIV or AIDS, leukemia, alkyl ting agents, or corticosteroid therapy, regardless of immunization status and children who travel to areas where measles is endemic or contact with travelers to endemic areas are at high risk of(4).
As a result of the existence of highly effective measles vaccine (5) four million measles related deaths are averted from 2012-2014 (6) . Measles vaccine is a live attenuated virus vaccine and two doses recommended by world health organization to provide protection from measles (14). According to WHO-AFRO region of 2015 Status of the measles Elimination in the African Region, Ethiopia is among the eleven countries with major challenges, large population, insecurity, and high incidence of measles, frequent outbreaks and leadership gaps (14).
According to WHO Ethiopia is among the six countries with the most unvaccinated infants of (1.1million) in 2017 (25). Ethiopia is among the nations with low measles containing vaccine (MCV1) coverage and According to WHO, measles surveillance is a key element to achieving elimination goal (9). The objectives of measles surveillances are detecting ,identify, investigate, and manage outbreaks identifying geographic areas and age groups at high-risk and Evaluate vaccination strategies in order to improve measles control(4). In Ethiopia Measles, case-based surveillance is part of the national public health emergency management (PHEM) system.
Case-based measles surveillance was initiated in Ethiopia in 2003. Measles is one of the weekly reportable diseases in Ethiopia and the number of reported cases represents only a small proportion of the expected cases. Measles case usually comes to health facilities often after they develop complication. As a result, they are diagnosed as the complication rather than measles, which is one of the reasons for under reporting of measles cases (12). And the aim of this study was to analyze seven years (2013-2019) measles surveillance data of Bale zone by person, place and time. The analysis includes vaccination status, laboratory con rmation and case fatality rate among cases.

Methods And Materials Study Area
Bale zone is among twenty-one administrative zones of Oromia regional state. It is located in the Southeastern part of Oromia and is situated between 5°11´03´´N to 8°09´27´´North latitudes and 38°12 04´´E to 42°12´47´´East longitudes with an altitude ranges from 300 to 4377 meters above sea level. The Data were collected from line list, case based and Weekly IDSR report. Data abstracted in terms of person, place, time, case classi cation, vaccination status and nal outcome. Data abstracted by the investigator.

Data processing and analysis
The abstracted data entered and analyzed using Microsoft Excel, Pivot software. Arch JIS version 10.1 software was used to locate area and spot map of cases. Descriptive statistics median, standard deviation, and percentages was used to analyze measles surveillance data during 2013-2019. Prevalence, case fatality and vaccination status also calculated. Data were described by person, place and time. Tables' graph and gures presented the results.
Operational de nition Suspected measles case: Any person with fever and maculopapular generalized rash and cough, coryza or conjunctivitis OR any person in whom a clinician suspects measles 2. Con rmed measles case: A case with laboratory con rmation (positive IgM antibody) or epidemiologically linked to con rmed cases. Epidemiologically linked case: A suspected measles case living in the same or in adjacent district with a laboratory con rmed case where there is a likelihood of transmission; onset of rash of the two cases being within 30 days of each other.4. Measles death: Any death from an illness that occurs in a con rmed case or epidemiologically linked case of measles within one month of the onset of rash.5. Discarded: A suspected measles case that has been completely investigated, including the collection of adequate blood specimen (5 ml), but lacks serologic evidence of recent measles virus infection (that is, IgM negative). 6. Clinical / Compatible: A suspected measles case that has not had a blood specimen taken for serologic con rmation, and cannot be epidemiologically linked to a laboratory-con rmed case.

Case Fatality by Age
Case fatality by age group showing of high case fatality rate of 4/1000 among less than one year of age followed by 3.8/1000 case fatality among 5-15 age category and low among age group of greater than 16 years. As age increase, the fatality of the case is decrease.

Trend of measles CF by Year
Regarding the trend of measles mortality, the greatest case fatality was occurred during 2015, which was 5.   nding is in line with the study conducted in Guji zone which shows all age groups, even older than 15 years are affected (20) and national measles surveillance data analysis nding of the age group 1 to 4 years was the most affected population by measles from all other age categories (21). This is because of malnutrition and inadequate vaccination status.
From 2013-2019 the highest measles prevalence rates were seen in 2015 and 2019 accounted for 21 per 100,000 and 141 per 100,000 populations respectively. The study nding is higher compared to study conducted in Nigeria , incidence was estimated at 19/100,000 population/year (22), in Ethiopia the incidence was more than 2 / 100,000 populations/year for ve years (21). The deference is possibly due to high accumulation of susceptible person and outbreak occurs frequently in the zone.
During 2013-2019 a total of 993 (24%) of total measles cases samples were sent to central laboratory for con rmation and about 248(24.9%) were measles IgM positive ,375 (37.7%) are discarded and 137(13.8%) are negative cases. This nding is in line with study conducted in south Ethiopia and Oromia region with 1507 (31.3%) samples were positive for measles (23) and 36% of samples were positive for Measles IgM respectively (13) . And greater than national con rmed cases in 2008 and 2009 only 10.7 and 9.1% are con rmed respectively (21) . These shows strength of surveillance system of the zone From 2013-2019 years periods 582 (13.2%) measles cases were admitted and 3659 (86.2%) suspected measles cases were treated as an outpatient level. The overall admission rate from the cases was 15.9 %. The admitted cases were lower as compared to study conducted in Addis Ababa among 1787 measles cases; 1442 (84%) were outpatient visits while the rest 276 (16%) were inpatient (18). This is due to there is a limited resource among patients and inadequacy of admission rooms in the study area Case fatality rate was 3.07/1000 population and high among children less than 1-year 4/1000 followed by 5-15 years with 3.8/1000. Fatality was high among females than males with CCFR of 3.3/1000 among females and 2.8/1000 among males respectively. The fatality of the zone was low as compared to study in Niger CRF of 9.7% and highest CFR was among infants (15.7%) (24). The expected Casefatality rate in Ethiopia is between 3% and 6%; In certain high-risk populations, case-fatality rates reach 30% in infants aged less than 1 year of age in Ethiopia (4). This is because CFR of measles decrease with increasing age and fatal in under ve.
Out of the 4241 total cases patients 2620(62%) of cases are vaccinated. There were 890(21%) case patients with no vaccination history and 731(17.2%) of the case patients have unknown vaccination status. Study nding is greater compared to study conducted in Ethiopia 380 (22%) were received at least one dose of measles containing vaccine (MCV) while 415 (24%) were not vaccinated and the rest 923 (54%) vaccination status were not known (18) .The study nding is lower than the study conducted in Oromia region 29% measles cases were not vaccinated and 46.4% of cases were unknown for vaccination status (13) .And study conducted in Guji zone a proportion (77%) of measles cases were unvaccinated (20) .
Over all from 4241 suspected measles cases were reported, 376 (27%) of suspected measles cases were reported by case based. while 3841(73%) were reported by line list from these the majority2753 (71.7%) was reported in 2019 because of outbreak. There were no reported measles cases by line list during 2018 and 2017 year this shows there is sensitivity of the surveillance system and case noti cation is good.
Measles case-based surveillance is part of the national PHEM system and a key component of the measles control program. It is a system whereby every suspected measles case should be detected, reported and undergo laboratory investigation (21).
Regarding seasonal pattern of measles, the highest number of measles cases are reported during June 1344(31.6%), may 934(22%) and July 545(12%) season of the year and low number of cases were reported in October November and September 85(2%),41(0.97%) and 98(2.3%) of cases respectively. Cases reach peak level in June .This nding is contrary with the nding of study conducted in Ethiopia, there was a trend of increment of cases in January, February and March (21) . This is due to about 60% of the zone climate were characterized by long persistent dry season (kola).

Limitation of the study
The study does not include the analysis of sample collected for laboratory by place and time, because the line list and case based was not complete. Vitamin A Supplemented for case patients was not included. Because death in the community was not reported case fatality was underestimated. Time lines and completeness was not included because of incomplete data

Strength of the study
The studies try to address all measles cases data type and all variables. Include 2019 data because ve districts of the zone were attacked by outbreak. To analyze all related variables of the study, use measles case-based report and line list.

Conclusion
Totally, 4241 measles cases reported with a crude case fatality of 3.07/1000 which is very high. The highest percentage of cases are males 2197(50.6%) with female to male ratio of 1:

Recommendation
Surveillance system should strengthen to notify and identify cases early in the community. Health facilities and health o ces of the districts in the zone should investigated and report measles death in the community. Samples collected for Laboratory con rmation should be improved in terms of quality and quantity by facilities. Routine immunization program should be strengthened by health posts and facilities in the zone. The zone should strengthen early preparedness and supplementary immunization activities before April to overcome changes in seasonal patterns of measles cases. The possible cause of measles in Ginir district should be further investigated.

Declarations
Competing of interest: -No con ict of interest Funding: -None Contribution GT conceptualized the study and methodology, collected all data, performed data analysis and wrote the original draft and the manuscript. YG contributed to the conceptualization of the study and methodology reviewed and edited the manuscript. GG and NA contributed reviewed and edited the manuscript. All authors read and approved the nal manuscript.