Date: Fri 6 Jul 2018, 5:00 PM
Source: WHO Weekly Bulletin on Outbreaks and Other Emergencies [edited]
<http://apps.who.int/iris/bitstream/handle/10665/273028/OEW27-300606072018.pdf?sequence=1&isAllowed=y>

Event Description
-----------------
Liberia has continued to experience sporadic cases of Lassa fever since the beginning of 2018. In week 25 (week ending 26 Jun 2018), 2 new confirmed Lassa fever cases were reported in Nimba County, the only county with active transmission currently. Nimba County has reported 5 confirmed Lassa fever cases since [12 May 2018]. In the latest event (the 2 confirmed cases in week 25), the 1st case-patient, a 59-year- old male from Gbehlay Geh district, fell ill on [4 Jun 2018] and was treated with antimalarials and antibiotics at a local clinic. On [20 Jun 2018], the case-patient presented to a public hospital with fever and other constitutional symptoms, and had bleeding from a venepuncture site.

On [21 Jun 2018], a blood specimen was collected and sent to the National Public Health Reference Laboratory (NPHRL). The test result released on [26 Jun 2018] was positive for Lassa fever virus infection. The 2nd case-patient, a 41-year-old female, is the wife of the first case-patient (described above). She developed illness on [17 Jun 2018] and was admitted to the same hospital on [20 June 2018] with fever and other constitutional symptoms. Being a known contact, a blood specimen was collected on [21 Jun 2018] and the test result released on [26 Jun 2018] was positive for Lassa fever. The 2 case-patients are admitted under barrier nursing and ribavirin treatment initiated. A total of 26 contacts, including 13 health workers, have been line listed and are being followed up.

Between [1 Jan 2018] and [27 Jun 2018], a total of 130 suspected Lassa fever cases, including 33 deaths, were reported. Of these, 20 cases were laboratory confirmed, 103 were discarded (after testing negative), and 7 cases were not tested due to inadequate specimens. Of the 20 confirmed cases, 14 have died, giving a case fatality rate of 70 percent. Females make up 60 percent (12) of the confirmed cases. The age range for the confirmed cases is 1 to 65 years old, with a median of 32.5 years. The confirmed cases are from 5 counties, namely (Nimba (9), Bong (4), Montserrado (3), Margibi (2), and Grand Bassa (2).

Public Health Actions
---------------------
- The Ministry of Health and the National Public Health Institute of Liberia (NPHIL) are coordinating response activities to the Lassa fever outbreak, with support from WHO, CDC and other partners. The national epidemic preparedness and response committee (NEPRC), under the leadership of NPHIL, have been meeting weekly to review the Lassa fever outbreak situation and provide technical support to sub-national level, with technical support from WHO, and US-CDC; 15 WHO field offices are providing technical and operational support to the response.
- Active surveillance, including case search, case investigation and contact tracing are ongoing in the affected districts. A specimen transport system using couriers is available at designated points across the country to transport specimens to the NPHRL for testing.
- The Ganta United Methodist Hospital has been designated as a treatment centre, and equipped with ribavirin and other medical supplies for case management. Orientation of healthcare workers on case management protocol is ongoing.
- Healthcare workers in the country are being trained on Lassa fever case management and infection prevention and control (IPC) measures by NPHIL and MOH, with support from WHO.
- Health workers' exposure risk assessment is planned to be conducted in the clinic or hospital where the confirmed cases sought care.
- Community engagement activities are ongoing in the affected communities, including home visits and providing information on environmental cleanliness.

Situation Interpretation
------------------------
Sporadic Lassa fever cases continue to occur in certain parts of Liberia where the disease is known to be endemic. Bong, Grand Bassa, Margibi, and Nimba are among the counties that report cases annually. In 2017, a total of 30 confirmed cases were reported from 7 counties. The reason for these sporadic cases is known: the constant interaction of rats (the vector for Lassa fever virus) and people in unsanitary conditions. The national authorities and partners need to prioritize measures mitigating this exposure risk factor by improving vector and environmental management components of the response. This goes along with effective social mobilization and community engagement strategies, targeting vector control and environmental management in the communities. There is also a need to enhance capacity at the subnational levels for early case detection, case investigation, appropriate case management and its associated IPC [infection prevention and control] measures aimed at averting infection among health workers.
========================
[The number of Lassa fever cases in Liberia continues to slowly increase. Between 1 Jan 2018 and 27 Jun 2018, 20 cases were laboratory confirmed, up from 18 cases on 1 Jun 2018. Apparently, all these Lassa fever virus infections were acquired by contact with infected rodents or their excretions. Lassa fever virus can be acquired from infected rodents or patients in the hospital but in the above report, there is no mention of Lassa fever virus nosocomial transmission. Transmission can occur in health facilities when personal protective equipment is not employed and barrier-nursing practices are not adequate to protect staff from blood and secretions of infected patients. The hospitals attending the patients mentioned above do have barrier measures in place.

As mentioned in previous posts, Lassa fever virus transmission to humans occur when people are in contact with the reservoir rodent host, the multimammate mouse (_Mastomys natalensis_ and _M. erythroleucus_) and the African wood mouse (_Hylomycus pamfi_) or their excreta, as was likely the situation in these cases. Rodent control has to be undertaken at the village level with individual households employing the preventive measures listed above. This requires an extensive and continuous public education effort.

Images of the _Mastomys natalensis_ mouse, the rodent reservoir of Lassa fever virus, can be seen at
<https://www.inaturalist.org/taxa/45326-Mastomys-natalensis> and of
_M. erythroleucus_ and _Hylomycus pamfi_ at:
<http://punchng.com/nigerias-large-rat-population-threatens-lassa-fever-war/>. - ProMED Mod.TY]

[Maps of Liberia can be accessed at:
<http://www.theworldmap.net/country/big/liberia/> and
<http://healthmap.org/promed/p/54>]
Date: Fri 15 Jun 2018
Source: WHO Regional Office for Africa, Health Information and Risk Assessment [edited]
<http://apps.who.int/iris/bitstream/handle/10665/272848/OEW24-815062018.pdf>

Weekly bulletin on outbreaks and other emergencies week 24: [11-17 Jun 2018; data as of 15 Jun 2018]
----------------------------------------------------------------------
Liberia: 2930 cases, 14 deaths, 0.5 percent CFR

Event description
-----------------
Liberia has been experiencing recurrent measles outbreaks since the beginning of 2018. In week 23 (week ending 10 Jun 2018), a total of 61 new suspected measles cases (with no deaths) were reported from 13 out of the 15 counties in the country, compared to 72 new cases reported in week 22 [week ending 3 Jun 2018]. 23 blood specimens collected from the suspected cases have been shipped to the National Reference Laboratory, while 20 of the case-patients had epidemiological links to confirmed cases. During the reporting week, 14 out of 92 health districts (in 5 counties) attained measles epidemic threshold of 3 laboratory confirmed cases. The 5 counties are Grand Bassa, Margibi, Maryland, Montserrado, and Nimba.

Between week 1 and week 23 of 2018 [1 Jan-10 Jun 2018], a total of 3086 suspected measles cases were reported. Of these, 177 were laboratory confirmed, 1762 had epidemiological links to confirmed cases, 562 were clinically compatible, 156 were discarded (after testing negative), and test results for 429 cases were pending. Of the 2930 confirmed, epidemiologically linked, clinically compatible, and suspected cases, 14 have died, giving a case fatality rate of 0.5 percent in this group; 558 (19 percent) were vaccinated, 334 (11 percent) were not vaccinated and 2 038 (70 percent) had unknown vaccination status. About 39 percent of the affected people are 4 years of age and below, 25 percent are between 5 and 9 years and 36 percent are 10 years and above.

Public health actions
---------------------
The Ministry of Health Expanded Program on Immunization and the National Public Health Institute of Liberia (NPHIL) are coordinating response activities to the measles outbreak, with support from WHO, UNICEF, and other partners. The national epidemic preparedness and response committee (NEPRC), under the leadership of NPHIL and with technical support from WHO, UNICEF, US-CDC and other agencies, have been meeting weekly to review the measles outbreak situation and provide technical support to sub-national level. WHO has deployed the Polio STOP team in the 15 counties to support sub-national level response.

A nation-wide measles immunization campaign has been conducted across the country in 3 phases since 15 Feb 2018, targeting a total of 654 803 children aged 6-59 months. Preliminary data indicates that 97 percent (63 350) of the targeted populations were vaccinated across the country.

Active search for measles cases continues throughout the country and has been reinforced in districts and communities with sustained outbreaks. Epidemic threshold is monitored weekly across the country through routine data collection and analysis.

All measles cases are being provided with symptomatic management along with a high dose of vitamin A.

The National Public Health Reference Laboratory has been testing samples reported across the country, by serology (IgM detection), and routinely releasing test results.

Communities have been provided with education to seek early care for measles cases at the nearest health facility. Communities have also mobilized through town criers, radio messaging, and posters to ensure high coverage of the immunization campaign among targeted age group.

Situation interpretation
------------------------
Liberia has been experiencing recurrent measles outbreaks since the beginning of the year [2018]. The reason for these outbreaks is known: the accumulation of a large number of susceptible populations over the years due to suboptimal immunization coverage. It is concerning that measles incidence cases are occurring in spite of the 3 phases of mass immunization campaigns conducted since February 2018, with seemingly high administrative coverage. The national authorities and partners need to drastically and speedily reduce the number of susceptible individuals in the most affected age-groups, maintain the build-up of vulnerable individuals at very low levels by immunising a large proportion (over 95 percent) of each new birth cohort and implement additional vaccination activities to periodically protect susceptible individuals who have accumulated.

With the well-developed immunization programme, structures, and systems, such measles outbreaks should be predicted and adequate preparedness measures put in place. Additionally, each measles outbreak should be followed by thorough evaluation of the cause of the outbreak, the surveillance system for early outbreak detection, the preparedness measures preceding the outbreak and the management of the outbreak, and an overall review of immunization programme goals and operations.
==========================
[A map showing the geographical distribution of measles cases in Liberia, week 1-23, 2018 can be seen at the source URL above. - ProMED Sr.Tech.Ed.MJ]

[HealthMap/ProMED-mail map of Liberia:
<http://healthmap.org/promed/p/54>.]
Date: Wed 13 Jun 2018
Source: Daily Observer [edited]
<https://www.liberianobserver.com/news/health-authorities-respond-to-lassa-fever-outbreak/>

The National Public Health Institute of Liberia (NPHIL) in collaboration with the Ministry of Health (MoH) has responded to the Lassa fever outbreak in the country.  According to a release issued in Monrovia, cases of Lassa fever are on the increase in the Lassa belt (Bong, Nimba, and Grand Bassa Counties).

In the country, 4 new confirmed cases have been reported: from Bong (2), Grand Bassa (1) and Nimba (1) since the last outbreak in May 2018. A blood specimen was collected and tested positive for Lassa fever on 4-7 Jun 2018 at the National Public Health Reference Laboratory (NPHRL). The recent case from Nimba County was confirmed by the NPHRL on 7 Jun [2018].

A total of 128 contacts, including 59 healthcare workers, have been line-listed and are being followed up. One case is currently undergoing treatment at Phebe Hospital in Gbarnga Bong County, while one has been discharged; 2 deaths have been reported in this recent outbreak.

Since the beginning of January 2018, a total of 112 suspected cases have been reported across the country, of which 18 have been confirmed positive by RT-PCR (Nimba-7, Montserrado-3, Bong-4, Margibi-2, and Grand Bassa-2. The case fatality rate among confirmed cases is 72.2 percent (13/18). The high death rate is alarming to NPHIL, which has launched an in-depth investigation.

The release also discloses that although Lassa fever is not new to Liberia, it is a deadly viral disease that requires urgent attention. The disease is spread by rodents (rats) through close contact with affected persons [or contaminated environments - ProMED Mod.TY].

People are advised to keep their environment clean: cover dishes to prevent rats from defecating or urinating on them; cover food in tightly closed containers to prevent rats from playing in food or drinking water; do not eat rats because you can get the sickness by coming into contact with their blood, urine or feces, and do not dry food in open places where rats can reach.

Other preventive measures are to avoid body contact with affected persons and endemic zones; visit a health facility immediately when you feel sick.

Meanwhile, NPHIL, MOH, and partners have appealed to the general public to take the necessary preventive measures, and to kindly report cases of fever to the nearest health facility.

"We continue to improve our rapid response at the county, district and community levels through the County Emergency Operation Centers, and to provide technical, financial and logistical support to the outbreaks, the release concluded.
=====================
[The number of confirmed Lassa fever cases in Liberia has increased somewhat since 1 Jun 2018, from 13 to 18 cases.

Lassa fever virus can be acquired from infected rodents or patients in the hospital. In the above report, there is no mention of Lassa fever virus nosocomial transmission. The situation where these people acquired Lassa fever virus is not indicated in these cases.

Virus transmission to humans occurs when people are in contact with the reservoir rodent host, the multimammate mouse (_Mastomys natalensis_ and _M. erythroleucus_) and the African wood mouse (_Hylomycus pamfi_) or their excreta, as was likely the situation in these cases. Rodent control has to be undertaken at the village level with individual households employing the preventive measures listed above. This requires an extensive and continuous public education effort. Transmission can occur in health facilities when personal protective equipment is not employed and barrier-nursing practices are not adequate to protect staff from blood and secretions of infected patients.

Images of the _Mastomys natalensis_ mouse, the rodent reservoir of Lassa fever virus, can be seen at
<https://www.inaturalist.org/taxa/45326-Mastomys-natalensis> and _M. erythroleucus_ and _Hylomycus pamfi_ at:
<http://punchng.com/nigerias-large-rat-population-threatens-lassa-fever-war/>. - ProMED Mod.TY]

[Maps of Liberia can be accessed at:
<http://www.theworldmap.net/country/big/liberia/> and
<http://healthmap.org/promed/p/54>.]
Date: Fri 1 Jun 2018
Source: The Bush Chicken [edited]
<http://www.bushchicken.com/nyenswah-says-13-out-of-73-lassa-fever-cases-confirmed/>

Tolbert Nyenswah, Director General of the National Public Health Institute of Liberia, says Liberia has reported 73 suspected cases of Lassa fever, with 13 confirmed.

At the beginning of May [2018], the Margibi County Health Team declared a health emergency following 2 confirmed cases of Lassa fever deaths in less than a week.

The newly assigned county health officer, Dr. Myers Pajibo, told a press briefing that the 2 cases involve a 56-year-old male and a 35-year-old female, who both showed signs of the fever by profusely vomiting with blood and subsequently dying on 3 and 5 May [2018], respectively, at the C. H. Rennie Hospital in Kakata.

Pajibo noted that the specimen taken from the deceased had been confirmed by the medical reference lab as Lassa fever, leaving the County Health Team with no alternative but to treat the case as a medical emergency.

During last week's Ministry of Information regular press briefing, Nyenswah said from January 2018 to the 2nd week of May, 73 suspected cases was reported with 13 confirmed. He also confirmed on 1 Jun [2018] that there had not been any additional deaths.

He explained that the current outbreak of Lassa fever can be found in Nimba, Bong, Lofa, and Grand Bassa.

He said health authorities are receiving reports about the disease from the 93 districts and 760 health facilities across the country on a weekly basis.

"There are evidence that the disease is leaving Nimba, Bong, Lofa and Grand Bassa to Montserrado, Margibi and Grand Kru," he said.

Nyenswah said health authorities have been able to bring the disease under control but he added that Lassa fever is endemic as people continue to eat rats or leave their food uncovered.

"The challenge in containing the disease is with the population awareness," he added.

The NPHIL director general said the disease had been brought under control but emphasized that measures are being put into place to respond to the disease in Margibi.

"Over 200 000 units of the medication meant to treat patients with the disease are in the country," he pointed out.

He stressed that health authorities do not want to see cases of the disease increasing and that the public must adhere to basic hygiene and continue to wash their hands, cover food, and desist from eating rats.

The World Health Organization's website notes that Lassa fever's initial symptoms include fever and general weakness, followed by a headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhea, cough, and abdominal pain.

The health body noted that humans could be exposed to the disease by encountering feces or urine from rodents and urged good community hygiene that discourages rodents from entering homes.  [Byline: Zeze Ballah]
=======================
[It is good to learn that there are no additional Lassa Fever deaths since mid-May 2018. Lassa fever virus can be acquired from infected rodents or patients in the hospital.  In the above report, there is no mention of Lass fever virus nosocomial transmission. The situation where these people acquired Lassa fever virus is not indicated in these cases except for a  2-year-old girl, who likely got the virus from her infected mother. Virus transmission to humans occurs when people are in contact with the reservoir rodent host, the multimammate mouse (_Mastomys ntalensis_ and _M. erythroleucus_) and the African wood mouse (_Hylomycus pamfi_) or their excreta, as was likely the situation in these cases. Rodent control has to be undertaken at the village level with individual households employing the preventive measures listed above. This requires an extensive and continuous public education effort. Transmission can occur in health facilities when personal protective equipment is not employed and barrier-nursing practices are not adequate to protect staff from blood and secretions of infected patients.

Images of the _Mastomys natalensis_ mouse, the rodent reservoir of Lassa fever virus, can be seen at <https://www.inaturalist.org/taxa/45326-Mastomys-natalensis> and _M. erythroleucus and _Hylomycus pamfi_  at: <http://punchng.com/nigerias-large-rat-population-threatens-lassa-fever-war/>. - ProMED Mod.TY]

[Maps of Liberia: <http://www.theworldmap.net/country/big/liberia/> and
<http://healthmap.org/promed>.]
Date: Wed 16 May 2018
Source: Xinhua [edited]
<http://www.xinhuanet.com/english/2018-05/16/c_137184127.htm>

Liberian authorities on Wednesday [16 May 2018] confirmed that 22 deaths have been recorded across the country following the outbreak of Lassa fever since January [2018].

In a statement, the National Public Health Institute of Liberia said the West African country had seen an increase in the outbreak with 81 suspected cases recorded so far.

However, 67 out of the 81 suspected cases tested negative following laboratory examination, according to the statement.

Lassa fever is a viral haemorrhagic fever caused by the Lassa virus.

The outbreak has so far occurred in Bong, Margibi, Nimba, and Montserrado, 4 counties out of Liberia's 15 counties.

The Liberian health authorities decried the high death rate, saying it was mostly caused by sick people coming to health facilities late for medical examination.

"Although Lassa fever is not new to Liberia, it is a deadly viral disease that requires urgent attention," the official statement said.

Humans usually become infected with the Lassa virus from exposure to urine or feces of infected _Mastomys_ [multimammate] rats. Other than common preventive measures such as washing hands regularly, the World Health Organization has recommended keeping cats.
=====================
[An earlier report indicated that there is an ongoing outbreak of Lassa fever in Liberia this year (2018). A 13 Apr 2018 WHO report stated that for the year 2018 until 13 Apr 2018, there were 67 suspected cases, and 9 confirmed cases have occurred in 6 counties. The above report indicated that 4 counties are involved in the current outbreak: Bong, Margibi, Nimba, and Montserrado, but the number of confirmed cases has increased to 22 fatal ones.

The situation where these Lassa fever cases acquired Lassa fever virus is not indicated. Virus transmission to humans occurs when people are in contact with the reservoir rodent host, the multimammate mouse (in the genus _Mastomys_) or its excreta, as was likely the situation in these cases. Rodent control has to be undertaken at the village level with individual households employing the preventive measures. This requires an extensive and continuous public education effort. Transmission also occurs in health facilities when personal protective equipment is not employed and barrier-nursing practices are not adequate to protect staff from blood and secretions of infected patients.

Images of the _Mastomys_ mouse, the rodent reservoir of Lassa fever virus, can be seen at
<https://www.inaturalist.org/taxa/45326-Mastomys-natalensis>. - ProMED Mod.TY]

[Maps of Liberia: <http://www.theworldmap.net/country/big/liberia/> and
<http://healthmap.org/promed/p/54>]
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