Introduction and patients develop mental deterioration and other

Introduction
Human
African Trypanosomiasis (HAT), or sleeping
sickness, is a vector-borne disease caused by the protozoan
parasite Trypanosoma brucei and
transmitted by tsetse flies, Glossina
spp. There are two forms: Trypanosoma
brucei gambiense which presents a chronic manifestation mainly in humans in
Ccentral
and Wwestern
Africa and Trypanosoma brucei rhodesiense
which presents acute severe symptoms in humans and also causes Animal African
Trypanosomiasis (nagana) in livestock and wildlife in Eeastern
and Ssouthern
Africa. Between the 1980s and the 1990s, African countries experienced epidemics
of HAT with an estimated 300,000 cases; therefore, the governments and foreign donors applied intensive
programmes of vector-control, active and
passive case detection and improvements in the availability and access to
treatment. This
effort made it possible to decrease the number of new HAT cases to 2,804 in 2015(1). However, in Uganda which is the only
country presenting both active T.b. gambiense in the north west and T.b. rhodesiense in the south east, T.b. rhodesiense has been
spreadingd spread KF1 northward due to
the movement of livestock and people and thisit
has resulted in the difference between the foci of
Gambian and Rhodesian HAT becoming only 150km in 2005(2). This merger would make diagnosis
and treatment more difficult since they differ in the two forms of the diseases
relying on a basis of human patients’ geographical data. It is urgent to control
the expansion of T.b. rhodesiense. My main objective of this essay is to discuss the current
situation of T.b. rhodesiense among
human and cattle populations in Uganda.

Epidemiology of Rhodesian HAT (rHAT) in
Uganda

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Rhodesian HAT clinically
progresses in two stages. In the first stage, patients show symptoms of chancre
at the site of the tsetse bite, intermittent fevers, severe headaches, irritability,
extreme fatigue and enlarged lymph nodes. In the second stage, the trypanosomes
cross the blood-brain barrier to invade the central nervous system and patients
develop mental deterioration and other neurologic problems, which leads to death
within six months unless treated.

T.b.rhodesiense was traditionally
endemic in Bugiri, Busia, Kayunga, Junja, Iganga, Kamuli, Mayuge, Mukono,
Pallisa and Tororo districts until the 1980s.
However, the epidemic began in new districts, namely, Masindi, Sotori,
Kaberamaido and Lira between 1998 and 2004. In recent data from 2009,
approximately a 24.3
% of the Ugandan population are at risk of infection of rHAT(3). The population at risk areis
people who engage in cattle raising or live near a livestock market since it is
shown that the distance to the livestock
market is directly linked to an increased risk of rHAT(4). Compared to that over
300 cases that had been reported annually in the
early 2000s, it has steadily decreased to 28 cases in 2015 since the Public Private
partnership, Stamp Out Sleeping Sickness Program (SOS) in eastern
Uganda was widely implemented. However, many of the reported
cases are detected in the second stage and the cases can be underreported.

Epidemiology of
African Animal Trypanosomiasis (AAT) in cattle

T. congolense, T. vivax and T. brucei spp.
cause AAT in cattle. In Uganda, it is estimated that approximately a
third of the herd; 19 million head were at risk from AAT in 2002(5). The disease is usually chronic and the major
clinical signs are anaemia, intermittent fevers and enlarged lymph nodes.
However, T.b. rhodesiense in
indigenous cattle is asymptomatic, the cattle maintain parasites acting as a
reservoir increasing the risk of infection to humans. Co-infection with T. congolense or T. vivax eventually cause death in cattle if not
treated. AAT has the most severe impact of economic loss in livestock productivity in Uganda. A previous study showed that a tick-borne disease and trypanosomiasis
diminish the productivity of draft cattle by
21% and household income from the use of oxen by 32% equivalent to US $245
annually(6).

Diagnosis and
Treatment

The diagnosis
for rHAT is the detection of trypanosomes from blood or chancre aspirate by microscopy. T.b. rhodesiense can be more frequently observed in blood in the
first stage than T.b.
gambiense, but the two species cannot be differentiated
by microscopy. Lumbaer puncture
follows to define the clinical stage and chemotherapeutic choice from presence
of the parasites and the number of white cells in the cerebrospinal fluid (CSF). Molecular diagnosis is available using Real Time
Polymerase Chain Reaction (qPCR) KF2 or
Loop-Mediated ?Isothermal Amplification (LAMP) to detect the serum
resistance-associated (SRA) gene, which can differentiate the species.  There are no rapid diagnostic tests (RDTs) for
T.b. rhodesiense, in contrast, RDTs are used for screening T.b. gambiense in health facilities.

The
treatment for the first stage is suramin, given by intravenous injection.  Adverse reaction is frequent but usually mild
and reversible. Since suramin does not cross the blood–brain barrier to kill trypanosomes
in the CSF, patients at the second stage are treated with melarsoprol, which is
the only drug available for the second stage. However, It causes severe adverse
reactions such as reactive encephalopathy and polyneuropathy, it leads to death in 1-5%
of patients with an 8.4% of fatality rate(7). All drugs are provided free of charge by the World Heath
Organization.   

In cattle, the clinical diagnosis is difficult because symptoms are
unspecific. Microscopic examination of blood is used for the detection of trypanosomes.
Curative treatment is diminazene diaceturate. Drugs such as isometamidium chloride and
quinapyramine sulphate and chloride can be used as prophylaxes.  No vaccines are available for humans and cattle.

Surveillance

In human health, the National Sleeping Sickness
Control Program by the Ministry
of Health is responsible for HAT national surveillance in Uganda. Due
to the transition from active surveillance to passive in 2005, it now relies
on case reports from the health care system. In newly affected districts, namely,
Dokolo, Kaberamaido,
Sotori and Serere, three county-level
hospitals provide diagnosis and free treatment for any referral patients. It is
very important that health care workers at a lower level in the health system,
where people at risk of the infection can visit, have knowledge about HAT and
refer the suspected patients to those referral hospitals. A previous study
showed that only 60 % of the health care workers at parish level in those four4
districts were aware of HAT and the major source of information was radio and
newspaper accounting for 40%(8). The reinforcement of the referral system and the training
of health care workers at the community level are vital to find cases at an early
stage.

The prevalence infection of trypanosomes among cattle is unknown. The
official policy, Uganda’s Animal Disease Act, restricts the movement of
livestock from endemic areas of AAT to non-endemic areas and all cattle in
endemic areas must be treated with trypanocidal treatment by a veterinary
officer(9). According to the interviews
with farmers in Sotori and Serere Districts, it is not regularly enforced and
even when it is done, they are not informed of what treatment was given to cattle
by the veterinary officer(10). In these areas, the
livestock movement restriction is widely understood by
farmers due to the past outbreaks of Foot and Mouth Disease. Enhancing
compliance with regulation of cattle movement and the treatment among the
veterinary officers and farmers will prevent spreading AAT and other tick-borne diseases to other regions.

Control

There are three
main methods for controlling T.b. rhodesiense: tsetse control, mass treatment of cattle, and early
detection and management of rHAT cases. In terms of vector control, there are a
wide range of techniques such as sequential aerial spraying or ground spraying of pyrethroids, tsetse trapping, odor
baits, selective bush clearing and the release of sterile males to reduce
transmissions. However, spaying of insecticides has to be implemented widely,
which is expensive and dependent on donor support.

Decreasing
the prevalence of T.b. rhodesiense in cattle interrupts transmission among
human and cattle populations; cattle are
the main reservoir for T.b. rhodesiense. Restricted application (RAP) is a method of spraying
insecticides on tsetse predilection sites, the legs and belly of cattle, which
is effective and three times cheaper than the traditional pour-on method(11). This also can prevent tick bites, which causes
other infectious diseases and anemia in cattle. In the SOS program,
approximately 500,000 cattle were treated with insecticides and a single dose
of trypanocides. The result shows a 75% decrease in the prevalence of T.b. rhodesiense in cattle in seven districts(12). This approach is more feasible and sustainable
for farmers with limited resources.

 

Conclusion

To prevent the further expansion
of T.b.
rhodesiense, firstly, the health services and training
health care workers should be reinforced, which will increase number of
detecting cases. Secondly, the enforcement of veterinary policy should be strengthened
in terms of preventing cattle and humans from contracting the infection
and increasing the productivity of livestock. Finally, better communication
and coordination among health care workers veterinary personnel, and communities
will enable them to localize the affected areas immediately to address the
disease control.

 KF1Could
continue to be spreading
now…so is the past tense better in this context?

 KF2If
not repeated, is it not necessary to write acrynom?

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